Multifunctional Raman Crystals: Comparison
View Latest Version
Please note this is a comparison between Version 2 by Vivi Li and Version 1 by Shibo Dai.

In the past few decades, the multifunctional optical crystals for all-solid-state Raman lasers have been widely studied by many scholars due to their compactness, convenience and excellent performance. In this entry, we briefly show two kinds of multifunctional Raman crystals: self-Raman (laser and Raman effects) crystals and self-frequency-doubled Raman (frequency-doubling and Raman effects) crystals. 

  • multifunctional crystal
  • Raman laser
  • self-Raman
  • self-frequency-doubled Raman

1. Introduction

Stimulated Raman scattering (SRS) is a simple and efficient method to extend the spectral range from ultraviolet to mid-infrared. In 1962, the SRS phenomenon was first detected by Woodbury and Ng when they studied Q-switched ruby lasers with nitrobenzene materials [1]. Thereafter, SRS was observed in liquid and gases. Compared with gas and liquid Raman media, solid-state Raman media have many excellent features such as good thermodynamic performance, narrow Raman line width and stable chemical properties, which are conducive to the generation of the Raman lasers with high reliability and high repetition frequency. A rapid expansion in the number of international research reports have emerged on yellow and eye-safe crystalline Raman lasers aimed at the development of practical devices for a wide range of applications, such as biomedical diagnostics, remote sensing, and laser therapies. Yellow and eye-safe crystalline Raman lasers can be obtained with a combination of frequency doubling and Raman effects, as well as the laser and Raman effects, respectively. Normally, these solid-state Raman laser sources need separate laser and Raman crystals or separate Raman and frequency doubling crystals, which results in a complex structure and a large insertion loss.

During recent decades, the multifunctional Raman optical crystal has emerged as a special kind of crystal, which possesses several effects within one crystal. As a result, the multifunctional Raman optical crystal has the advantages of compactness, easy operation, and low insertion loss [2]. Up to now, most multifunctional Raman optical crystals are self-Raman crystals with laser and Raman properties [3,4], and only a few multifunctional Raman optical crystals are self-frequency-doubled Raman crystals, with both frequency-doubled and Raman properties [5,6]. There are four kinds of self-Raman crystals: tungstate, vanadate, molybdate and silicate crystals. In 1985, the first self-Raman laser was realized by Andryunas et al. [7] with Nd ion doped tungstate potassium Nd:KGW/Nd:KYW at the flashlamp pump. Afterwards, there were no reports on self-Raman lasers for more than ten years, but the types of self-Raman media have been constantly increased in number [8,9,10]. In 1999, the first passively Q-switched (PQS) self-Raman laser was demonstrated with a Yb:KGW crystal by Lagatsky et al. [11]. In the following year, the first actively Q-switched (AQS) self-Raman laser was realized by Findeisen et al. [12] with the anisotropic Nd:KGW crystal. In 2002, Grabtchikov et al. [13] demonstrated the first continuous wave (CW) self-Raman laser with Yb:KYW crystal, and the corresponding optical power conversion efficiency was 10%. The vanadate YVO

During recent decades, the multifunctional Raman optical crystal has emerged as a special kind of crystal, which possesses several effects within one crystal. As a result, the multifunctional Raman optical crystal has the advantages of compactness, easy operation, and low insertion loss [2]. Up to now, most multifunctional Raman optical crystals are self-Raman crystals with laser and Raman properties [3][4], and only a few multifunctional Raman optical crystals are self-frequency-doubled Raman crystals, with both frequency-doubled and Raman properties [5][6]. There are four kinds of self-Raman crystals: tungstate, vanadate, molybdate and silicate crystals. In 1985, the first self-Raman laser was realized by Andryunas et al. [7] with Nd ion doped tungstate potassium Nd:KGW/Nd:KYW at the flashlamp pump. Afterwards, there were no reports on self-Raman lasers for more than ten years, but the types of self-Raman media have been constantly increased in number [8][9][10]. In 1999, the first passively Q-switched (PQS) self-Raman laser was demonstrated with a Yb:KGW crystal by Lagatsky et al. [11]. In the following year, the first actively Q-switched (AQS) self-Raman laser was realized by Findeisen et al. [12] with the anisotropic Nd:KGW crystal. In 2002, Grabtchikov et al. [13] demonstrated the first continuous wave (CW) self-Raman laser with Yb:KYW crystal, and the corresponding optical power conversion efficiency was 10%. The vanadate YVO

4

 and GdVO

4 were later predicted to be excellent materials for SRS [14], and many vanadate self-Raman lasers have been gradually reported with high average powers (>5 W) and high conversion efficiencies (>20%) [15,16,17,18,19,20]. Moreover, the inclusion of second-harmonic generation (SHG) or sum-frequency generation (SFG) crystals has been verified to be an effective approach for yellow-orange-red generation with average output power up to 8.8 W and diode-visible power conversion efficiency of >30% [21]. Until now, only a few self-frequency-doubled Raman crystals have been demonstrated. For instance, in 2009, Liu et al. [5] used a single KTA crystal to perform self-frequency-doubled Raman conversion from the 1064 nm fundamental beam to the 573 nm yellow beam. Another self-frequency-doubled Raman crystal, BTM, was reported by Gao et al. [6] in 2013, and a maximum pulse energy of 5.6 mJ was attained for 589 nm yellow laser radiation.

were later predicted to be excellent materials for SRS [14], and many vanadate self-Raman lasers have been gradually reported with high average powers (>5 W) and high conversion efficiencies (>20%) [15][16][17][18][19][20]. Moreover, the inclusion of second-harmonic generation (SHG) or sum-frequency generation (SFG) crystals has been verified to be an effective approach for yellow-orange-red generation with average output power up to 8.8 W and diode-visible power conversion efficiency of >30% [21]. Until now, only a few self-frequency-doubled Raman crystals have been demonstrated. For instance, in 2009, Liu et al. [5] used a single KTA crystal to perform self-frequency-doubled Raman conversion from the 1064 nm fundamental beam to the 573 nm yellow beam. Another self-frequency-doubled Raman crystal, BTM, was reported by Gao et al. [6] in 2013, and a maximum pulse energy of 5.6 mJ was attained for 589 nm yellow laser radiation.

2. The Classification of Multifunctional Raman Crystals

2.1. Self-Raman Crystals

2.1.1. Vanadate

As the most popular multifunctional Raman crystal, the vanadate self-Raman crystals include Nd:YVO

4 [15,16,20,21,22,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63], Nd:GdVO

[15][16][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62], Nd:GdVO

4 [18,19,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78], Yb:YVO

[18][19][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77], Yb:YVO

4 [17], and Nd:LuVO

[17], and Nd:LuVO

4 [79,80]. Among these self-Raman laser crystals, Nd:YVO

[78][79]. Among these self-Raman laser crystals, Nd:YVO

4

 has been the most extensively researched and widely employed due to its large Raman gain coefficient, strong absorption of pump radiation over a broad bandwidth, and large emission cross section. Its strongest vibrational Raman mode is located at 890 cm

−1

 with Raman line width of 3.0 cm

−1 and Raman gain coefficient of ~5 cm/GW [14]. In addition, two weak Raman shifts are 816 and 259 cm

and Raman gain coefficient of ~5 cm/GW [14]. In addition, two weak Raman shifts are 816 and 259 cm

−1

 with respective Raman gain coefficients of 2.6 and 2.3 cm/GW for c-cut Nd:YVO

4 crystal with Z(XX) scattering configuration [60]; and 840 and 379 cm

crystal with Z(XX) scattering configuration [59]; and 840 and 379 cm

−1

 with respective Raman gain coefficients of 2.6 and 0.9 cm/GW for a-cut Nd:YVO

4 crystal with X(ZZ) scattering configuration [81]. The Nd-doped YVO

crystal with X(ZZ) scattering configuration [80]. The Nd-doped YVO

4

 crystal belongs to the zircon type D

4h

 tetragonal space group, and its stimulated radiation cross section parallel to the c axis (a-cut, σ = 25 × 10

−19

 cm

2

 at 1064 nm) is four times higher than the cross section orthogonal to the c axis (c-cut, σ = 6.5 × 10

−19

 cm

2 at 1066 nm) [24]. 

at 1066 nm) [23]. 

In 2004, the first PQS Nd:YVO

4 self-Raman laser was demonstrated by Chen [24], as shown in 

self-Raman laser was demonstrated by Chen [23], as shown in 

Figure 1. At the incident pump power of 2.0 W, the laser system produced 0.125 W of average output power at 1178.6 nm with 6.3% of conversion efficiency from diode power to Raman output power. Then, Chen [15,16] demonstrated the AQS Nd:YVO

. At the incident pump power of 2.0 W, the laser system produced 0.125 W of average output power at 1178.6 nm with 6.3% of conversion efficiency from diode power to Raman output power. Then, Chen [15][16] demonstrated the AQS Nd:YVO

4

 self-Raman lasers at 1176 and 1525 nm with maximum average output powers of 1.5 and 1.2 W, respectively, corresponding to conversion efficiencies of 13.9% and 8.9%. In 2006, the first CW Nd:YVO

4 self-Raman laser was realized by Burakevich et al. [27], and the maximum output power at 1177 nm was 50 mW with optical power conversion efficiency of 2%. In 2008, a passively mode-locked Nd:YVO

self-Raman laser was realized by Burakevich et al. [26], and the maximum output power at 1177 nm was 50 mW with optical power conversion efficiency of 2%. In 2008, a passively mode-locked Nd:YVO

4 self-Raman laser at 1176 nm was obtained by M. Weitz [29] with a slow saturable absorber, and maximum average power of 420 mW was delivered with a duration of 4.8 ps and a repetition rate of 73 MHz. An efficient AQS eye-safe Raman laser at 1525 nm using a double-end diffusion-bonded Nd:YVO

self-Raman laser at 1176 nm was obtained by M. Weitz [28] with a slow saturable absorber, and maximum average power of 420 mW was delivered with a duration of 4.8 ps and a repetition rate of 73 MHz. An efficient AQS eye-safe Raman laser at 1525 nm using a double-end diffusion-bonded Nd:YVO

4 crystal was reported by Chang et al. [31] in 2009, and average power of 2.23 W was generated with a conversion efficiency of 13%. In 2016, a high power CW YVO

crystal was reported by Chang et al. [30] in 2009, and average power of 2.23 W was generated with a conversion efficiency of 13%. In 2016, a high power CW YVO

4

/Nd:YVO

4

/YVO

4 self-Raman laser at 1176 nm, pumped by a wavelength-locked 878.9 nm diode laser, was reported by Fan et al. [20], corresponding to maximum output power of 5.3 W and optical conversion efficiency of 20%. To our knowledge, this is the highest power and efficiency among Nd:YVO

self-Raman laser at 1176 nm, pumped by a wavelength-locked 878.9 nm diode laser, was reported by Fan et al. [20], corresponding to maximum output power of 5.3 W and optical conversion efficiency of 20%. To our knowledge, this is the highest power and efficiency among Nd:YVO

4

 self-Raman lasers up to now. In addition, self-Raman lasers in combination with SHG or SFG can be used to produce yellow light sources. In 2007, the first CW yellow laser at 588 nm was realized by intracavity frequency doubling Nd:YVO

4 self-Raman laser [28], corresponding to maximum yellow output power of 140 mW and diode-to-yellow conversion efficiency of 4.4%, respectively. In 2019, a 4.0 W CW Nd:YVO

self-Raman laser [27], corresponding to maximum yellow output power of 140 mW and diode-to-yellow conversion efficiency of 4.4%, respectively. In 2019, a 4.0 W CW Nd:YVO

4 self-Raman yellow laser at 588 nm was reported by Chen [59] with conversion efficiency of 12.7%. In 2020, Chen [21] demonstrated an efficient intracavity frequency-doubled AQS Nd:YVO

self-Raman yellow laser at 588 nm was reported by Chen [58] with conversion efficiency of 12.7%. In 2020, Chen [21] demonstrated an efficient intracavity frequency-doubled AQS Nd:YVO

4

 self-Raman yellow laser at 588 nm with maximum output power of 8.8 W and diode-to-yellow conversion efficiency of 34%. To the best of our knowledge, this is the highest power and efficiency among self-Raman yellow lasers. In the same year, a PQS YVO

4

/Nd:YVO

4

/YVO

4 self-Raman yellow laser at 589 nm was demonstrated by Chen et al. [63]. Maximum output power of 0.66 W was attained with an optical conversion efficiency of 3.8%. 

self-Raman yellow laser at 589 nm was demonstrated by Chen et al. [62]. Maximum output power of 0.66 W was attained with an optical conversion efficiency of 3.8%. 

Crystals 11 00114 g001 550

Figure 1.

 Schematic of the passively Q-switched Nd:YVO

4 self-Raman laser [24].

self-Raman laser [23].

Nd:GdVO

4

 crystal is the isostructural body of the Nd:YVO

4

 crystal, which also has a zircon structure with tetragonal space group. Compared to the Nd:YVO

4

 crystal, the Nd:GdVO

4

 crystal has higher thermal conductivity, which could be beneficial for high power self-Raman laser operation. The strongest Raman shift mode of the Nd:GdVO

4

 crystal is 882 cm

−1

 with line width of 3.5 cm

−1 and Raman gain coefficient of 4.5 cm/GW [66]. In addition, the secondary Raman transition is located at 382 cm

and Raman gain coefficient of 4.5 cm/GW [65]. In addition, the secondary Raman transition is located at 382 cm

−1 for the X(ZZ)X configuration, and the corresponding Raman gain was estimated to be 0.7cm/GW [73]. 

for the X(ZZ)X configuration, and the corresponding Raman gain was estimated to be 0.7cm/GW [72]. 

In 2004, Chen [

64

] reported a PQS Nd:GdVO

4

 self-Raman laser at 1175.6 nm by using a Cr

4+

:YAG saturable absorber, and maximum peak power of 8.4 kW was obtained with conversion efficiency of 7%. Due to its large emission cross section and short upper state lifetime, the Cr

4+

:YAG saturable absorber is not suitable for the PQS Nd:GdVO

4 self-Raman laser [65]. In the same year, benefiting from its large absorption cross section and thermal conductivity, the LiF:F

self-Raman laser [64]. In the same year, benefiting from its large absorption cross section and thermal conductivity, the LiF:F

2−

 crystal was employed as a saturable absorber to realize the PQS Nd:GdVO

4 self-Raman laser [65]. Maximum peak power of 9 kW was achieved with conversion efficiency of 2%. Several months later, the first AQS Nd:GdVO

self-Raman laser [64]. Maximum peak power of 9 kW was achieved with conversion efficiency of 2%. Several months later, the first AQS Nd:GdVO

4 self-Raman laser operating at 1521 nm was delivered by Chen [18] as exhibited in 

self-Raman laser operating at 1521 nm was delivered by Chen [18] as exhibited in 

Figure 2

, and maximum output power of 1.18 W was achieved with an optical-to-optical conversion efficiency of 8.7%. In 2012, a 4.1 W CW Nd:GdVO

4 self-Raman laser using double-end polarized pumping at 880 nm was realized by Lin et al. [74] with an optical conversion efficiency of 11.2%. To our knowledge, this is the highest power among Nd:GdVO

self-Raman laser using double-end polarized pumping at 880 nm was realized by Lin et al. [73] with an optical conversion efficiency of 11.2%. To our knowledge, this is the highest power among Nd:GdVO

4 self-Raman lasers. In 2013, Wang et al. [75] demonstrated a PQS Nd:GdVO

self-Raman lasers. In 2013, Wang et al. [74] demonstrated a PQS Nd:GdVO

4

 self-Raman laser at 1176 nm with maximum output power of 0.52 W and optical-to-optical conversion efficiency of 10.3%. Additionally, yellow light sources were obtained through intracavity SHG or SFG of the Nd:GdVO

4 self-Raman lasers. In 2008, a 2.51 W CW yellow emission at 586.5 nm was demonstrated by Lee et al. [68] through intracavity frequency-doubling of a Nd:GdVO

self-Raman lasers. In 2008, a 2.51 W CW yellow emission at 586.5 nm was demonstrated by Lee et al. [67] through intracavity frequency-doubling of a Nd:GdVO

4

 self-Raman laser. Two years later, a 5.3 W CW laser emission at 559 nm with high efficiency (21%) was achieved by intracavity sum-frequency mixing of fundamental and first-Stokes emission in a self-Raman Nd:GdVO

4 laser [69]. 

laser [68]. 

Crystals 11 00114 g002 550

Figure 2.

 Schematic of actively Q-switched Nd:GdVO

4 self-Raman laser [18].

self-Raman laser [18].

Compared to Nd:YVO

4

 crystal, Yb:YVO

4

 crystal has the strong and comparatively broad absorption band near 985 nm, the extremely low quantum defect (~3.5%), and the broad gain bandwidth (~30 nm). Moreover, Yb:YVO

4

 crystal has a moderate Raman gain coefficient of 4.5 cm/GW at a Raman shift of 892 cm

−1

. In 2005, the PQS Yb:YVO

4 self-Raman laser at 1119.5 nm was achieved by Kisel et al. [17] with pulse energy of 3.6 μJ and pulse duration of 6 ns.

self-Raman laser at 1119.5 nm was achieved by Kisel et al. [17] with pulse energy of 3.6 μJ and pulse duration of 6 ns.

Similar to the Nd:YVO

4

 and Nd:GdVO

4

 crystals, the Nd:LuVO

4

 crystal also has a zircon structure and a space group of I4

1

/amd. Compared to the Nd:YVO

4

 and Nd:GdVO

4

 crystals, the Nd:LuVO

4

 crystal has larger emission cross section (14.6 × 10

−19

 cm

2

) and absorption cross section (6.9 × 10

−19

 cm

2

). Moreover, the Nd:LuVO

4 crystal has a high damage threshold [83,84], and is easy to process. Its Raman frequency shift was determined to be 900 cm

crystal has a high damage threshold [81][82], and is easy to process. Its Raman frequency shift was determined to be 900 cm

−1

 with a line width of 5 cm

−1 and Raman gain coefficient above 3.2 cm/GW [80]. In 2009, a PQS Nd:LuVO

and Raman gain coefficient above 3.2 cm/GW [79]. In 2009, a PQS Nd:LuVO

4 self-Raman laser at 1178.8 nm was demonstrated by Kaminskii et al. [79], corresponding to maximum output power of 0.12 W and conversion efficiency of 5%, respectively. In 2010, Lu et al. [80] reported an efficient CW double-end diffusion-bonded Nd:LuVO

self-Raman laser at 1178.8 nm was demonstrated by Kaminskii et al. [78], corresponding to maximum output power of 0.12 W and conversion efficiency of 5%, respectively. In 2010, Lu et al. [79] reported an efficient CW double-end diffusion-bonded Nd:LuVO

4

 self-Raman yellow laser at 589 nm with maximum output power of 3.5 W and conversion efficiency of 13.3%.

2.1.2. Tungstate

According to our surveys, tungstate self-Raman crystals include Nd:KGd(WO

4

)

2 (Nd:KGW) [2,12,85,86,87,88,89,90,91,92,93,94], Yb:KGd(WO

 (Nd:KGW) [2][12][83][84][85][86][87][88][89][90][91][92], Yb:KGd(WO

4

)

2 (Yb:KGW) [11,95,96,97], Nd:PbWO

(Yb:KGW) [11][93][94][95], Nd:PbWO

4 (Nd:PWO) [98], Yb:KY(WO

(Nd:PWO) [96], Yb:KY(WO

4

)

2 (Yb:KYW) [13], Nd:BaWO

(Yb:KYW) [13], Nd:BaWO

4 [99], Nd:SrWO

[97], Nd:SrWO

4 [99,100], Yb:KLu(WO

[97][98], Yb:KLu(WO

4

)

2 (Yb:KLuW) [101] and Nd:KLu(WO

(Yb:KLuW) [99] and Nd:KLu(WO

4

)

2 (Nd:KLuW) [102].

(Nd:KLuW) [100].

The anisotropic Nd:KGW crystal is the most commonly used self-Raman crystal in tungstate. Nd:KGW crystal has a large emission cross section (4.3 × 10

−19

 cm

2) and a wide absorption spectrum [86]. In addition, this crystal can be doped with a high concentration of Nd ions without significant concentration quenching and deterioration of crystal quality. It has two strong Raman vibrational modes at 767 cm

) and a wide absorption spectrum [85]. In addition, this crystal can be doped with a high concentration of Nd ions without significant concentration quenching and deterioration of crystal quality. It has two strong Raman vibrational modes at 767 cm

−1

 (

Ng

) and 901 cm

−1

 (

Nm

) in orthogonal orientations with similar Raman line width of 5.4 cm

−1, and the corresponding Raman gain coefficients are 4.4 and 3.3 cm/GW, respectively [26]. 

, and the corresponding Raman gain coefficients are 4.4 and 3.3 cm/GW, respectively [25]. 

In 1985, the first self-Raman conversion was observed by Andryunas et al. [85] in Nd:KGW and Nd:KYW crystals, and output energy of 11 mJ was obtained with conversion efficiency of 6.14%. In 1999, the first PQS Nd:KGW self-Raman laser at 1181 nm was realized by Grabtchikov et al. [86], corresponding to output power of 4.8 mW and conversion efficiency of 0.7%, respectively. In 2000, the first acousto-optic Q-switched Nd:KGW self-Raman laser at 1162 nm was achieved by Findeisen et al. [12] with maximum pulse energy of 0.1 mJ. Later, Raman radiation was converted into the yellow laser at 581 nm by the external frequency-doubling technology with the LiB

In 1985, the first self-Raman conversion was observed by Andryunas et al. [83] in Nd:KGW and Nd:KYW crystals, and output energy of 11 mJ was obtained with conversion efficiency of 6.14%. In 1999, the first PQS Nd:KGW self-Raman laser at 1181 nm was realized by Grabtchikov et al. [85], corresponding to output power of 4.8 mW and conversion efficiency of 0.7%, respectively. In 2000, the first acousto-optic Q-switched Nd:KGW self-Raman laser at 1162 nm was achieved by Findeisen et al. [12] with maximum pulse energy of 0.1 mJ. Later, Raman radiation was converted into the yellow laser at 581 nm by the external frequency-doubling technology with the LiB

3

O

5

 crystal, and the schematic diagram is displayed in 

Figure 3

.

Crystals 11 00114 g003 550

Figure 3. Schematic of the first actively Q-switched self-Raman laser [12].

Schematic of the first actively Q-switched self-Raman laser [12].

In 2005, Demidovich et al. [2] reported the first CW Nd:KGW self-Raman laser at 1181 nm with maximum output power of 54 mW and conversion efficiency of 2.6%, as depicted in 

In 2005, Demidovich et al. [2] reported the first CW Nd:KGW self-Raman laser at 1181 nm with maximum output power of 54 mW and conversion efficiency of 2.6%, as depicted in 

Figure 4. In the same year, an AQS Nd:KGW self-Raman laser at 1181 nm was realized by Hamano et al. [90] with maximum output power of 0.8 W and optical conversion efficiency of 14%. In 2014, Tang et al. [94] reported a CW Nd:KGW self-Raman laser at 1077.9 nm with maximum output power of 0.42 W and conversion efficiency of 16.8%.

. In the same year, an AQS Nd:KGW self-Raman laser at 1181 nm was realized by Hamano et al. [88] with maximum output power of 0.8 W and optical conversion efficiency of 14%. In 2014, Tang et al. [92] reported a CW Nd:KGW self-Raman laser at 1077.9 nm with maximum output power of 0.42 W and conversion efficiency of 16.8%.

Crystals 11 00114 g004 550

Figure 4.  Schematic of the first continuous-wave self-Raman laser [2].

Compared to Nd:KGW crystal, Yb:KGW crystal is a promising material for high efficiency due to small quantum defect, high quantum efficiency, and broad absorption bandwidth. Moreover, Yb:KGW crystal is an ideal material for the self-Raman laser because of its large absorption cross section (5.3 × 10

−20

 cm

2

), large emission cross section (2.8 × 10

−20

 cm

2) and high nonlinear optical susceptibility [96]. Its two main Raman frequency shift modes are 768 cm

) and high nonlinear optical susceptibility [94]. Its two main Raman frequency shift modes are 768 cm

−1

 (

Ng

) and 901 cm

−1

 (

Nm). In 1999, the first PQS Yb:KGW self-Raman laser at 1139 nm was attained by Lagatsky et al. [11]. The maximum output power and pulse energy were 7 mW and 0.4 μJ, respectively. In 2003, Kisel et al. [95] demonstrated a PQS Yb:KGW self-Raman laser at 1145 nm with maximum output power of 0.11 W and conversion efficiency from fundamental-to-first Stokes as high as 40%. In 2013, a CW Yb:KGW self-Raman laser at 1110.5 nm was attained by Chang et al. [96], corresponding to the diode-to-Stokes conversion efficiency of 21.8% and highest output power of 1.7 W. In 2019, a quasi-CW Yb:KGW self-Raman laser at 1096 nm was reported by Ferreira et al. [97] with maximum output power of 4.5 W and optical conversion efficiency of 32%.

). In 1999, the first PQS Yb:KGW self-Raman laser at 1139 nm was attained by Lagatsky et al. [11]. The maximum output power and pulse energy were 7 mW and 0.4 μJ, respectively. In 2003, Kisel et al. [93] demonstrated a PQS Yb:KGW self-Raman laser at 1145 nm with maximum output power of 0.11 W and conversion efficiency from fundamental-to-first Stokes as high as 40%. In 2013, a CW Yb:KGW self-Raman laser at 1110.5 nm was attained by Chang et al. [94], corresponding to the diode-to-Stokes conversion efficiency of 21.8% and highest output power of 1.7 W. In 2019, a quasi-CW Yb:KGW self-Raman laser at 1096 nm was reported by Ferreira et al. [95] with maximum output power of 4.5 W and optical conversion efficiency of 32%.

Compared with the doped KGW crystal, tungstate Nd:PWO crystal has higher Raman gain coefficient (8.4 cm/GW), and the corresponding Raman shift is 901 cm

−1

 with line width of 4.3 cm

−1 [103]. In 2001, a PQS Nd:PWO self-Raman laser at 1170 nm was produced by Chen et al. [98] with maximum output energy of 2.5 μJ and conversion efficiency of 0.1%.

[101]. In 2001, a PQS Nd:PWO self-Raman laser at 1170 nm was produced by Chen et al. [96] with maximum output energy of 2.5 μJ and conversion efficiency of 0.1%.

The Yb:KYW crystal has a broad absorption band centered at 981 nm, relatively large absorption coefficient (17 cm

−1

 for the typical 5 at% Yb

3+ concentration), and relatively inexpensive, reproducible, and easy growth [13]. Its Raman frequency shift and Raman gain coefficient are 905 cm

concentration), and relatively inexpensive, reproducible, and easy growth [13]. Its Raman frequency shift and Raman gain coefficient are 905 cm

−1 and 5.1 cm/GW, respectively [103,104]. In 2002, Grabtchikov et al. [13] reported a PQS Yb:KYW self-Raman laser at 1130 nm with maximum output power of 2 mW.

and 5.1 cm/GW, respectively [101][102]. In 2002, Grabtchikov et al. [13] reported a PQS Yb:KYW self-Raman laser at 1130 nm with maximum output power of 2 mW.

Nd:BaWO

4

 and Nd:SrWO

4

 crystals have similar stimulated Raman scattering cross sections as Nd:KGW crystal. Raman gain coefficients are 8.5 and 5 cm/GW at the Raman shift modes of 926 and 921 cm

−1

, respectively, corresponding to the Raman line widths of 1.6 and 3.0 cm

−1 [99]. In 2004, a PQS Nd:SrWO

[97]. In 2004, a PQS Nd:SrWO

4 self-Raman laser at 1170 nm was generated by Jelinkova et al. [100] with a pulse energy of 1.3 mJ. In 2006, the PQS Nd:SrWO

self-Raman laser at 1170 nm was generated by Jelinkova et al. [98] with a pulse energy of 1.3 mJ. In 2006, the PQS Nd:SrWO

4

 self-Raman laser at 1170 nm and Nd:BaWO

4 self-Raman laser at 1169 nm were reported by Sulc et al. [99], and the corresponding pulse energies were 1.23 and 0.81 mJ, respectively.

self-Raman laser at 1169 nm were reported by Sulc et al. [97], and the corresponding pulse energies were 1.23 and 0.81 mJ, respectively.

Yb:KLuW crystal belongs to the monoclinic space group C

2/C, and its main absorption center and fluorescence lifetime are 981 nm and 375 μs, respectively. In addition, the physical and spectral properties of Yb:KLuW crystals are similar to those of Yb:KGW and Yb:KYW crystals [105]. The main Raman shift modes are located at 907 and 757 cm

, and its main absorption center and fluorescence lifetime are 981 nm and 375 μs, respectively. In addition, the physical and spectral properties of Yb:KLuW crystals are similar to those of Yb:KGW and Yb:KYW crystals [103]. The main Raman shift modes are located at 907 and 757 cm

−1 [105]. In 2005, Liu et al. [101] demonstrated a PQS Yb:KLuW self-Raman laser at 1137.6 nm, as illustrated in 

[103]. In 2005, Liu et al. [99] demonstrated a PQS Yb:KLuW self-Raman laser at 1137.6 nm, as illustrated in 

Figure 5

. Maximum output power of 0.4 W was obtained with conversion efficiency of 5.7%.

Crystals 11 00114 g005 550

Figure 5. Schematic diagram of the PQS Yb:KLuW self-Raman laser setup; LC, laser crystal; SA, saturable absorber [101].

Schematic diagram of the PQS Yb:KLuW self-Raman laser setup; LC, laser crystal; SA, saturable absorber [99].

Nd:KLuW crystal belongs to the monoclinic space group C

2/C

 with an emission wavelength of 1070 nm. The absorption cross section of Nd:KLuW crystal at 812 nm is 7.93 × 10

−20

 cm

2

, and the emission cross section at 1.07 μm is 2.4 × 10

−19

 cm

2 [106]. The two strongest Raman shifts are located at 907 and 757 cm

[104]. The two strongest Raman shifts are located at 907 and 757 cm

−1 [107]. In 2015, an AQS Nd:KLuW self-Raman laser at 1185 nm was produced by Cong et al. [102], as shown in 

[105]. In 2015, an AQS Nd:KLuW self-Raman laser at 1185 nm was produced by Cong et al. [100], as shown in 

Figure 6

, and the maximum output power of 1.5 W was attained with conversion efficiency of 9.8%.

Crystals 11 00114 g006 550

Figure 6.  Schematic diagram of the actively Q-switched Yb:KLuW self-Raman laser [102][100].

2.1.3. Molybdate

Molybdate self-Raman crystals consist of Nd:PbMoO

4

 crystal and Nd:SrMoO

4

 crystal. The Raman gain coefficient of Nd:PbMoO

4

 crystal is two or three times higher than those of YVO

4

, GdVO

4 and KGW crystals [108]. Its Raman frequency shift is 871 cm

and KGW crystals [106]. Its Raman frequency shift is 871 cm

−1

 with line width of 8.0 cm

−1 [107]. In 2005, the PQS Nd:PbMoO

[105]. In 2005, the PQS Nd:PbMoO

4 self-Raman laser at first Stoke wavelength of 1163 nm was reported by Basiev et al. [108] with pulse energy of 6 μJ.

self-Raman laser at first Stoke wavelength of 1163 nm was reported by Basiev et al. [106] with pulse energy of 6 μJ.

The a-cut Nd:SrMoO

4

 crystal has a peak emission cross section of 3 × 10

−19

 cm

2

 and fluorescence decay time of 180 ms. Its Raman gain coefficient (5.7 cm/GW) is comparable to those of YVO

4

 and GdVO

4 crystals [109]. The Raman shift of Nd:SrMoO

crystals [107]. The Raman shift of Nd:SrMoO

4

 crystal is 887 cm

−1

 with line width of 2.5 cm

−1 [107]. In 2009, Basiev et al. [109] demonstrated a PQS Nd:SrMoO

[105]. In 2009, Basiev et al. [107] demonstrated a PQS Nd:SrMoO

4

 self-Raman laser, as exhibited in 

Figure 7

. Maximum pulse energy of 21 μJ was obtained at a wavelength of 1163 nm.

Crystals 11 00114 g007 550

Figure 7.

 Schematic diagram of the PQS Nd:GdVO

4 self-Raman laser: LD, laser diode; L, focusing lens; C, laser crystal; VSA, saturable absorber with variable transmission; OC, output coupler [109].

self-Raman laser: LD, laser diode; L, focusing lens; C, laser crystal; VSA, saturable absorber with variable transmission; OC, output coupler [107].

2.2. Self-Frequency-Doubled Raman Crystals

2.2.1. KTiOAsO4 (KTA) and KTiOPO4 (KTP)

KTA crystal has an orthorhombic structure with non-centro-symmetric point group C

2v

 (mm

2

) and space group Pna2

1

 (Z58). Due to the high nonlinear coefficient (d

33

 = 16.2 pm/V) and high damage threshold (>300 MW/cm

2), KTA crystal has been used in optical parametric oscillators (OPOs) since the 1990s [111,112]. In 1996, Tu et al. [113] proved that KTA is an excellent Raman medium with Raman gain coefficients of ~2.5 cm/GW at 234 cm

), KTA crystal has been used in optical parametric oscillators (OPOs) since the 1990s [108][109] In 1996, Tu et al. [110] proved that KTA is an excellent Raman medium with Raman gain coefficients of ~2.5 cm/GW at 234 cm

−1

 and ~0.6 cm/GW at 671 cm

−1

, respectively, and corresponding Raman line widths of 5.8 and 19 cm

−1. The KTA crystal was first reported by Liu et al. [5] as a self-frequency-doubled Raman crystal in 2009, as displayed in 

. The KTA crystal was first reported by Liu et al. [5] as a self-frequency-doubled Raman crystal in 2009, as displayed in 

Figure 8

. The KTA self-frequency-doubled Raman laser at 573 nm was realized with Raman shift of 671 cm

−1

, and maximum output power of 0.82 W was obtained with conversion efficiency of 7.5%.

Crystals 11 00114 g008 550

Figure 8.

 Schematic diagram of the KTiOAsO

4 (

KTA) self-frequency-doubled Raman laser [5]: LD, laser diode; CL, coupling lens; RM, rear mirror; OC, output coupler; DM, dichroic mirror; AO, acousto-optic; AR, antireflection; HT, high transmission; HR, high reflection.

KTP crystal belongs to the family of KTA crystal. KTP crystal possesses the superior qualities of a high nonlinear coefficient and a high damage threshold [114]. In 2005, KTP crystal was recognized as a self-frequency-doubled Raman crystal by Chen [114], and its strongest Raman shift is 270 cm

KTP crystal belongs to the family of KTA crystal. KTP crystal possesses the superior qualities of a high nonlinear coefficient and a high damage threshold [111]. In 2005, KTP crystal was recognized as a self-frequency-doubled Raman crystal by Chen [111], and its strongest Raman shift is 270 cm

−1

 with Raman gain coefficient of ~2.5 cm/GW. As depicted in 

Figure 9

, the KTP self-frequency-doubled Raman laser at 548 nm was realized from the AQS 1064 nm Nd:YAG laser, and maximum output power of 0.25 W was obtained with conversion efficiency of 2.5%.

Crystals 11 00114 g009 550

Figure 9. Schematic diagram of the KTP self-frequency-doubled Raman laser [114]: AO, acousto-optic; PR, partial reflection; HT, high transmission; HR, high reflection.

Schematic diagram of the KTP self-frequency-doubled Raman laser [111]: AO, acousto-optic; PR, partial reflection; HT, high transmission; HR, high reflection.

2.2.2. BaTeMo2O9 (BTM)

BTM crystallized in a monoclinic system with space group P2

1 [115]. In 2012, Yu et al. confirmed that the BTM crystal has a wide transmission band (0.4–5 μm), large nonlinear coefficient (d

[112]. In 2012, Yu et al. confirmed that the BTM crystal has a wide transmission band (0.4–5 μm), large nonlinear coefficient (d

31

 = 9.88 pm/V) and high optical damage threshold (544 MW/cm

2), flexible phase-matching, and high chemical, and mechanical stabilities [116]. Its strongest Raman shift is 915.2 cm

), flexible phase-matching, and high chemical, and mechanical stabilities [113]. Its strongest Raman shift is 915.2 cm

−1

 with line width of ~4.4 cm

−1 [6]. In 2013, the BTM crystal was employed as self-frequency-doubled Raman crystal to generate the yellow laser at 589 nm, as illustrated in 

[6]. In 2013, the BTM crystal was employed as self-frequency-doubled Raman crystal to generate the yellow laser at 589 nm, as illustrated in 

Figure 10 [6]. Maximum pulse energy of 5.6 mJ was achieved at a pump pulse energy of 48 mJ, corresponding to optical-to-optical conversion efficiency of 11.7%.

[6]. Maximum pulse energy of 5.6 mJ was achieved at a pump pulse energy of 48 mJ, corresponding to optical-to-optical conversion efficiency of 11.7%.

Crystals 11 00114 g010 550

Figure 10. Schematic diagram of the BaTeMo2O9 (BTM) self-frequency-doubled Raman laser at 589 nm [6].

References

  1. Woodbury, E.; Ng, W. Ruby laser operation in near IR. Proc. Inst. Radio Eng. 1962, 50, 2367.
  2. Demidovich, A.; Grabtchikov, A.; Lisinetskii, V.; Burakevich, V.; Orlovich, V.; Kiefer, W. Continuous-wave Raman generation in a diode-pumped Nd3+:KGd(WO4)2 laser. Opt. Lett. 2005, 30, 1701–1703.
  3. Voronina, I.; Ivleva, L.; Basiev, T.; Zverev, P.; Polozkov, N. Active Raman media: SrWO4:Nd3+, BaWO4:Nd3+. Growth and Characterization. J. Optoelectron. Adv. Mater. 2003, 5, 887–892.
  4. Ivleva, L.; Basiev, T.; Voronina, I.; Zverev, P.; Osiko, V.; Polozkov, N. SrWO4:Nd3+–new material for multifunctional lasers. Opt. Mater. 2003, 23, 439–442.
  5. Liu, Z.; Wang, Q.; Zhang, X.; Zhang, S.; Chang, J.; Fan, S.; Sun, W.; Jin, G.; Tao, X.; Sun, Y. Self-frequency-doubled KTiOAsO4 Raman laser emitting at 573 nm. Opt. Lett. 2009, 34, 2183–2185.
  6. Gao, Z.; Liu, S.; Zhang, J.; Zhang, S.; Zhang, W.; He, J.; Tao, X. Self-frequency-doubled BaTeMo2O9 Raman laser emitting at 589 nm. Opt. Express 2013, 21, 7821–7827.
  7. Andryunas, K.; Yishchakas, Y.; Kobelka, V.; Mochalov, I.; Pavlyuk, A.; Petrovskii, G.; Syrus, V. Self-SRS conversion of Nd3+ laser emission in crystals of double tungstates. Zh. Eksp. Teor. Fiz. Pis’ Ma Red. 1985, 42, 333–365.
  8. Kaminskii, A.; Eichler, H.; Grebe, D.; Macdonald, R.; Findeisen, J.; Bagayev, S.; Butashin, A.; Konstantinova, A.; Manaa, H.; Moncorge, R. Orthorhombic (LiNbGeO5): Efficient stimulated Raman scattering and tunable near-infrared laser emission from chromium doping. Opt. Mater. 1998, 10, 269–284.
  9. Kaminskii, A.A.; Ueda, K.-i.; Eichler, H.E.; Findeisen, J.; Bagayev, S.N.; Kuznetsov, F.A.; Pavlyuk, A.A.; Boulon, G.; Bourgeois, F. Monoclinic Tungstates KDy(WO4)2 and KLu(WO4)2-New χ(3)-Active Crystals for Laser Raman Shifters. Jpn. J. Appl. Phys. 1998, 37, L923.
  10. Kaminskii, A.A.; Bagayev, S.N.; Garsia, S.J.; Eichler, H.; Fernandez, J.; Jaque, D.; Findeisen, J.; Balda, R.; Agullo, R.F. First observations of stimulated emission and of stimulated Raman scattering in acentric cubic Nd3+:Bi12SiO20 crystals. Quantum Electron. 1999, 29, 6.
  11. Lagatsky, A.; Abdolvand, A.; Kuleshov, N. Passive Q switching and self-frequency Raman conversion in a diode-pumped Yb:KGd(WO4)2 laser. Opt. Lett. 2000, 25, 616–618.
  12. Findeisen, J.; Eichler, H.; Peuser, P. Self-stimulating, transversally diode pumped Nd3+:KGd(WO4)2 Raman laser. Opt. Commun. 2000, 181, 129–133.
  13. Grabtchikov, A.; Kuzmin, A.; Lisinetskii, V.; Orlovich, V.; Demidovich, A.; Danailov, M.; Eichler, H.; Bednarkiewicz, A.; Strek, W.; Titov, A. Laser operation and Raman self-frequency conversion in Yb:KYW microchip laser. Appl. Phys. B 2002, 75, 795–797.
  14. Kaminskii, A.A.; Ueda, K.-i.; Eichler, H.J.; Kuwano, Y.; Kouta, H.; Bagaev, S.N.; Chyba, T.H.; Barnes, J.C.; Gad, G.M.; Murai, T. Tetragonal vanadates YVO4 and GdVO4–new efficient χ(3)-materials for Raman lasers. Opt. Commun. 2001, 194, 201–206.
  15. Chen, Y.-F. High-power diode-pumped actively Q-switched Nd:YVO4 self-Raman laser: Influence of dopant concentration. Opt. Lett. 2004, 29, 1915–1917.
  16. Chen, Y.-F. Compact efficient all-solid-state eye-safe laser with self-frequency Raman conversion in a Nd:YVO4 crystal. Opt. Lett. 2004, 29, 2172–2174.
  17. Kisel, V.; Troshin, A.; Tolstik, N.; Shcherbitsky, V.; Kuleshov, N.; Matrosov, V.; Matrosova, T.; Kupchenko, M. Q-switched Yb3+:YVO4 laser with Raman self-conversion. Appl. Phys. B 2005, 80, 471–473.
  18. Chen, Y.-F. Efficient 1521-nm Nd:GdVO4 raman laser. Opt. Lett. 2004, 29, 2632–2634.
  19. Su, F.; Zhang, X.; Wang, Q.; Jia, P.; Li, S.; Liu, B.; Zhang, X.; Cong, Z.; Wu, F. Theoretical and experimental study on a diode-pumped actively Q-switched Nd:GdVO4 self-stimulated Raman laser at 1173 nm. Opt. Commun. 2007, 277, 379–384.
  20. Fan, L.; Zhao, W.; Qiao, X.; Xia, C.; Wang, L.; Fan, H.; Shen, M. An efficient continuous-wave YVO4/Nd:YVO4/YVO4 self-Raman laser pumped by a wavelength-locked 878.9 nm laser diode. Chin. Phys. B 2016, 25, 114207.
  21. Chen, Y.-F.; Chen, K.; Liu, Y.; Chen, C.; Tsou, C.; Liang, H. Criterion for optimizing high-power acousto-optically Q-switched self-Raman yellow lasers with repetition rates up to 500 kHz. Opt. Lett. 2020, 45, 1922–1925.
  22. Ding, S.; Zhang, X.; Wang, Q.; Su, F.; Jia, P.; Li, S.; Fan, S.; Chang, J.; Zhang, S.; Liu, Z. Theoretical and experimental study on the self-Raman laser with Nd:YVO4 crystal. IEEE J. Quantum Electron. 2006, 42, 927–933.
  23. Chen, Y.-F. Efficient subnanosecond diode-pumped passively Q-switched Nd:YVO4 self-stimulated Raman laser. Opt. Lett. 2004, 29, 1251–1253.
  24. Su, F.; Zhang, X.; Wang, Q.; Ding, S.; Jia, P.; Li, S.; Fan, S.; Zhang, C.; Liu, B. Diode pumped actively Q-switched Nd:YVO4 self-Raman laser. J. Phys. D Appl. Phys. 2006, 39, 2090.
  25. Wang, B.; Tan, H.; Peng, J.; Miao, J.; Gao, L. Low threshold, actively Q-switched Nd3+:YVO4 self-Raman laser and frequency doubled 588 nm yellow laser. Opt. Commun. 2007, 271, 555–558.
  26. Burakevich, V.; Lisinetskii, V.; Grabtchikov, A.; Demidovich, A.; Orlovich, V.; Matrosov, V. Diode-pumped continuous-wave Nd:YVO4 laser with self-frequency Raman conversion. Appl. Phys. B 2007, 86, 511–514.
  27. Lee, A.; Pask, H.; Omatsu, T.; Dekker, P.; Piper, J. All-solid-state continuous-wave yellow laser based on intracavity frequency-doubled self-Raman laser action. Appl. Phys. B 2007, 88, 539–544.
  28. Weitz, M.; Theobald, C.; Wallenstein, R.; L’huillier, J.A. Passively mode-locked picosecond Nd:YVO4 self-Raman laser. Appl. Phys. Lett. 2008, 92, 091122.
  29. Chen, X.; Zhang, X.; Wang, Q.; Li, P.; Cong, Z. Diode-pumped actively Q-switched c-cut Nd:YVO4 self-Raman laser. Laser Phys. Lett. 2008, 6, 26.
  30. Chang, Y.; Su, K.-W.; Chang, H.; Chen, Y.-F. Compact efficient Q-switched eye-safe laser at 1525 nm with a double-end diffusion-bonded Nd:YVO4 crystal as a self-Raman medium. Opt. Express 2009, 17, 4330–4335.
  31. Omatsu, T.; Lee, A.; Pask, H.; Piper, J. Passively Q-switched yellow laser formed by a self-Raman composite Nd:YVO4/YVO4 crystal. Appl. Phys. B 2009, 97, 799–804.
  32. Zhu, H.; Duan, Y.; Zhang, G.; Huang, C.; Wei, Y.; Chen, W.; Huang, Y.; Ye, N. Yellow-light generation of 5.7 W by intracavity doubling self-Raman laser of YVO4/Nd:YVO4 composite. Opt. Lett. 2009, 34, 2763–2765.
  33. Zhu, H.; Duan, Y.; Zhang, G.; Huang, C.; Wei, Y.; Shen, H.; Zheng, Y.; Huang, L.; Chen, Z. Efficient second harmonic generation of double-end diffusion-bonded Nd:YVO4 self-Raman laser producing 7.9 W yellow light. Opt. Express 2009, 17, 21544–21550.
  34. Wang, Z.; Du, C.; Ruan, S.; Zhang, L. LD-pumped Q-switched Nd:YVO4 self-Raman laser. Laser Phys. 2010, 20, 474–477.
  35. Kananovich, A.; Demidovich, A.; Danailov, M.; Grabtchikov, A.; Orlovich, V. All-solid-state quasi-CW yellow laser with intracavity self-Raman conversion and sum frequency generation. Laser Phys. Lett. 2010, 7, 573–578.
  36. Du, C.L.; Zhang, L.; Yu, Y.Q.; Ruan, S.; Guo, Y. 3.1 W laser-diode-end-pumped composite Nd:YVO4 self-Raman laser at 1176 nm. Appl. Phys. B 2010, 101, 743–746.
  37. Zhu, H.; Duan, Y.; Zhang, G.; Huang, C.; Wei, Y.; Chen, W.; Huang, L.; Huang, Y. Efficient continuous-wave YVO4/Nd:YVO4 Raman laser at 1176 nm. Appl. Phys. B 2011, 103, 559–562.
  38. Lü, Y.; Cheng, W.; Xiong, Z.; Lu, J.; Xu, L.; Sun, G.; Zhao, Z. Efficient CW laser at 559 nm by intracavity sum-frequency mixing in a self-Raman Nd:YVO4 laser under direct 880 nm diode laser pumping. Laser Phys. Lett. 2010, 7, 787.
  39. Fan, L.; Fan, Y.-X.; Wang, H.-T. A compact efficient continuous-wave self-frequency Raman laser with a composite YVO4/Nd:YVO4/YVO4 crystal. Appl. Phys. B 2010, 101, 493–496.
  40. Shuzhen, F.; Xingyu, Z.; Qingpu, W.; Zhaojun, L.; Lei, L.; Zhenhua, C.; Xiaohan, C.; Xiaolei, Z. 1097 nm Nd:YVO4 self-Raman laser. Opt. Commun. 2011, 284, 1642–1644.
  41. Li, X.; Lee, A.J.; Pask, H.M.; Piper, J.A.; Huo, Y. Efficient, miniature, cw yellow source based on an intracavity frequency-doubled Nd:YVO4 self-Raman laser. Opt. Lett. 2011, 36, 1428–1430.
  42. Duan, Y.; Zhu, H.; Huang, C.; Zhang, G.; Wei, Y. Potential sodium D2 resonance radiation generated by intra-cavity SHG of a c-cut Nd:YVO4 self-Raman laser. Opt. Express 2011, 19, 6333–6338.
  43. Duan, Y.; Zhang, G.; Zhang, Y.; Jin, Q.; Wang, H.; Zhu, H. LD end-pumped c-Cut Nd:YVO4/KTP self-Raman laser at 560 nm. Laser Phys. 2011, 21, 1859–1862.
  44. Chen, X.; Zhang, X.; Wang, Q.; Li, P.; Liu, Z.; Cong, Z.; Li, L.; Zhang, H. Highly efficient double-ended diffusion-bonded Nd:YVO4 1525-nm eye-safe Raman laser under direct 880-nm pumping. Appl. Phys. B 2012, 106, 653–656.
  45. Chen, W.; Wei, Y.; Huang, C.; Wang, X.; Shen, H.; Zhai, S.; Xu, S.; Li, B.; Chen, Z.; Zhang, G. Second-Stokes YVO4/Nd:YVO4/YVO4 self-frequency Raman laser. Opt. Lett. 2012, 37, 1968–1970.
  46. Shen, H.; Wang, Q.; Zhang, X.; Liu, Z.; Bai, F.; Cong, Z.; Chen, X.; Wu, Z.; Wang, W.; Gao, L. Simultaneous dual-wavelength operation of Nd:YVO4 self-Raman laser at 1524 nm and undoped GdVO4 Raman laser at 1522 nm. Opt. Lett. 2012, 37, 4113–4115.
  47. Ding, S.; Wang, M.; Wang, S.; Zhang, W. Investigation on LD end-pumped passively Q-switched c-cut Nd:YVO4 self-Raman laser. Opt. Express 2013, 21, 13052–13061.
  48. Huang, G.; Yu, Y.; Xie, X.; Zhang, Y.; Du, C. Diode-pumped simultaneously Q-switched and mode-locked YVO4/Nd:YVO4/YVO4 crystal self-Raman first-Stokes laser. Opt. Express 2013, 21, 19723–19731.
  49. Du, C.; Huang, G.; Yu, Y.; Xie, X.; Zhang, Y.; Wang, D. Q-switched mode-locking of second-Stokes pulses in a diode-pumped YVO4/Nd:YVO4/YVO4 self-Raman laser. Laser Phys. 2014, 24, 125003.
  50. Ding, X.; Fan, C.; Sheng, Q.; Li, B.; Yu, X.; Zhang, G.; Sun, B.; Wu, L.; Zhang, H.; Liu, J. 5.2-W high-repetition-rate eye-safe laser at 1525 nm generated by Nd:YVO4–YVO4 stimulated Raman conversion. Opt. Express 2014, 22, 29111–29116.
  51. Kores, C.C.; Jakutis-Neto, J.; Geskus, D.; Pask, H.M.; Wetter, N.U. Diode-side-pumped continuous wave Nd3+:YVO4 self-Raman laser at 1176 nm. Opt. Lett. 2015, 40, 3524–3527.
  52. Lin, H.; Huang, X.; Sun, D.; Liu, X. Passively Q-switched multi-wavelength Nd:YVO4 self-Raman laser. J. Mod. Opt. 2016, 63, 2235–2237.
  53. Zhu, H.; Guo, J.; Ruan, X.; Xu, C.; Duan, Y.; Zhang, Y.; Tang, D. Cascaded self-Raman laser emitting around 1.2–1.3 μm based on a c-cut Nd:YVO4 crystal. IEEE Photonics J. 2017, 9, 1–7.
  54. Zhu, H.; Guo, J.; Duan, Y.; Zhang, J.; Zhang, Y.; Xu, C.; Wang, H.; Fan, D. Efficient 1.7 μm light source based on KTA-OPO derived by Nd:YVO4 self-Raman laser. Opt. Lett. 2018, 43, 345–348.
  55. Bai, F.; Jiao, Z.; Xu, X.; Wang, Q. High power Stokes generation based on a secondary Raman shift of 259 cm−1 of Nd:YVO4 self-Raman crystal. Opt. Laser Technol. 2019, 109, 55–60.
  56. Chen, M.; Dai, S.; Zhu, S.; Yin, H.; Li, Z.; Chen, Z. Multi-watt passively Q-switched self-Raman laser based on a c-cut Nd:YVO4 composite crystal. Josa B 2019, 36, 524–532.
  57. Chen, Y.; Pan, Y.; Liu, Y.; Cheng, H.; Tsou, C.; Liang, H. Efficient high-power continuous-wave lasers at green-lime-yellow wavelengths by using a Nd:YVO4 self-Raman crystal. Opt. Express 2019, 27, 2029–2035.
  58. Chen, Y.; Liu, Y.; Gu, D.; Pan, Y.; Cheng, H.; Tsou, C.; Liang, H. High-power dual-color yellow–green solid-state self-Raman laser. Laser Phys. 2019, 29, 075802.
  59. Fan, L.; Zhao, X.-D.; Zhang, Y.-C.; Gu, X.-D.; Wan, H.-P.; Fan, H.-B.; Zhu, J. Multi-wavelength continuous-wave Nd:YVO4 self-Raman laser under in-band pumping. Chin. Phys. B 2019, 28, 084210.
  60. Liu, Y.; Chen, C.; Hsiao, J.; Pan, Y.; Tsou, C.; Liang, H.; Chen, Y. Compact efficient high-power triple-color Nd:YVO4 yellow-lime-green self-Raman lasers. Opt. Lett. 2020, 45, 1144–1147.
  61. Liu, P.; Qi, F.; Li, W.; Liu, Z.; Wang, Y.; Ding, X.; Yao, J. Self-Raman Nd-doped vanadate laser: A pump source of organic crystal based difference frequency generation. J. Mod. Opt. 2020, 67, 914–919.
  62. Chen, M.; Dai, S.; Yin, H.; Zhu, S.; Li, Z.; Chen, Z. Passively Q-switched yellow laser at 589 nm by intracavity frequency-doubled c-cut composite Nd:YVO4 self-Raman laser. Optics Laser Technol. 2021, 133, 106534.
  63. Chen, Y.-F. Compact efficient self-frequency Raman conversion in diode-pumped passively Q-switched Nd:GdVO4 laser. Appl. Phys. B 2004, 78, 685–687.
  64. Basiev, T.; Vassiliev, S.; Konjushkin, V.; Osiko, V.; Zagumennyi, A.; Zavartsev, Y.; Kutovoi, S.; Shcherbakov, I. Diode pumped 500-picosecond Nd:GdVO4 Raman laser. Laser Phys. Lett. 2004, 1, 237.
  65. Baoshan, W.; Huiming, T.; Jiying, P.; Jieguang, M.; Lanlan, G. Low threshold, diode end-pumped Nd3+:GdVO4 self-Raman laser. Opt. Mater. 2007, 29, 1817–1820.
  66. Dekker, P.; Pask, H.M.; Spence, D.J.; Piper, J.A. Continuous-wave, intracavity doubled, self-Raman laser operation in Nd:GdVO4 at 586.5 nm. Opt. Express 2007, 15, 7038–7046.
  67. Lee, A.; Pask, H.M.; Dekker, P.; Piper, J. High efficiency, multi-Watt CW yellow emission from an intracavity-doubled self-Raman laser using Nd:GdVO4. Opt. Express 2008, 16, 21958–21963.
  68. Lee, A.J.; Pask, H.M.; Spence, D.J.; Piper, J.A. Efficient 5.3 W cw laser at 559 nm by intracavity frequency summation of fundamental and first-Stokes wavelengths in a self-Raman Nd:GdVO4 laser. Opt. Lett. 2010, 35, 682–684.
  69. Lee, A.J.; Lin, J.; Pask, H.M. Near-infrared and orange–red emission from a continuous-wave, second-Stokes self-Raman Nd:GdVO4 laser. Opt. Lett. 2010, 35, 3000–3002.
  70. Lee, A.J.; Spence, D.J.; Piper, J.A.; Pask, H.M. A wavelength-versatile, continuous-wave, self-Raman solid-state laser operating in the visible. Opt. Express 2010, 18, 20013–20018.
  71. Omatsu, T.; Okida, M.; Lee, A.; Pask, H. Thermal lensing in a diode-end-pumped continuous-wave self-Raman Nd-doped GdVO4 laser. Appl. Phys. B 2012, 108, 73–79.
  72. Lin, J.; Pask, H.M. Cascaded self-Raman lasers based on 382 cm−1 shift in Nd:GdVO4. Opt. Express 2012, 20, 15180–15185.
  73. Lin, J.; Pask, H. Nd:GdVO4 self-Raman laser using double-end polarised pumping at 880 nm for high power infrared and visible output. Appl. Phys. B 2012, 108, 17–24.
  74. Wang, M.; Ding, S.; Yu, W.; Zhang, W. High-efficient diode-pumped passively Q-switched c-cut Nd:GdVO4 self-Raman laser. Laser Phys. Lett. 2013, 10, 045403.
  75. Lee, A.J.; Omatsu, T.; Pask, H.M. Direct generation of a first-Stokes vortex laser beam from a self-Raman laser. Opt. Express 2013, 21, 12401–12409.
  76. Lee, A.J.; Zhang, C.; Omatsu, T.; Pask, H.M. An intracavity, frequency-doubled self-Raman vortex laser. Opt. Express 2014, 22, 5400–5409.
  77. Ma, Y.; Lee, A.J.; Pask, H.M.; Miyamoto, K.; Omatsu, T. Direct generation of 1108 nm and 1173 nm Laguerre-Gaussian modes from a self-Raman Nd:GdVO4 laser. Opt. Express 2020, 28, 24095–24103.
  78. Kaminskii, A.; Bettinelli, M.; Dong, J.; Jaque, D.; Ueda, K. Nanosecond Nd3+:LuVO4 self-Raman laser. Laser Phys. Lett. 2009, 6, 374.
  79. Lü, Y.; Zhang, X.; Li, S.; Xia, J.; Cheng, W.; Xiong, Z. All-solid-state cw sodium D2 resonance radiation based on intracavity frequency-doubled self-Raman laser operation in double-end diffusion-bonded Nd3+:LuVO4 crystal. Opt. Lett. 2010, 35, 2964–2966.
  80. Li, R.; Bauer, R.; Lubeigt, W. Continuous-Wave Nd:YVO4 self-Raman lasers operating at 1109 nm, 1158 nm and 1231 nm. Opt. Express 2013, 21, 17745–17750.
  81. Maunier, C.; Doualan, J.; Moncorgé, R.; Speghini, A.; Bettinelli, M.; Cavalli, E. Growth, spectroscopic characterization, and laser performance of Nd:LuVO4 a new infrared laser material that is suitable for diode pumping. Josa B 2002, 19, 1794–1800.
  82. Zhao, S.; Zhang, H.; Wang, J.; Kong, H.; Cheng, X.; Liu, J.; Li, J.; Lin, Y.; Hu, X.; Xu, X. Growth and characterization of the new laser crystal Nd:LuVO4. Opt. Mater. 2004, 26, 319–325.
  83. Andriunas, K.; Vishchakas, I.; Kabelka, V.; Mochalov, I.; Pavliuk, A. Stimulated-Raman self-conversion of Nd3+ laser light in double tungstenate crystals. ZhETF Pisma Redaktsiiu 1985, 42, 333–335.
  84. Grabtchikov, A.; Kuzmin, A.; Lisinetskii, V.; Ryabtsev, G.; Orlovich, V.; Demidovich, A. Stimulated Raman scattering in Nd:KGW laser with diode pumping. J. Alloy. Compd. 2000, 300, 300–302.
  85. Grabtchikov, A.; Kuzmin, A.; Lisinetskii, V.; Orlovich, V.; Ryabtsev, G.; Demidovich, A. All solid-state diode-pumped Raman laser with self-frequency conversion. Appl. Phys. Lett. 1999, 75, 3742–3744.
  86. Ustimenko, N.S.; Gulin, A.V. New self-frequency converted Nd3+:KGd (WO4)2 Raman lasers. Quantum Electron. 2002, 32, 229.
  87. Omatsu, T.; Ojima, Y.; Pask, H.M.; Piper, J.A.; Dekker, P. Efficient 1181 nm self-stimulating Raman output from transversely diode-pumped Nd3+:KGd(WO4)2 laser. Opt. Commun. 2004, 232, 327–331.
  88. Hamano, A.; Pleasants, S.; Okida, M.; Itoh, M.; Yatagai, T.; Watanabe, T.; Fujii, M.; Iketaki, Y.; Yamamoto, K.; Omatsu, T. Highly efficient 1181 nm output from a transversely diode-pumped Nd3+:KGd(WO4)2 self-stimulating Raman laser. Opt. Commun. 2006, 260, 675–679.
  89. Jianhong, H.; Jipeng, L.; Rongbing, S.; Jinghui, L.; Hui, Z.; Canhua, X.; Fei, S.; Zongzhi, L.; Jian, Z.; Wenrong, Z. Short pulse eye-safe laser with a stimulated Raman scattering self-conversion based on a Nd:KGW crystal. Opt. Lett. 2007, 32, 1096–1098.
  90. Lisinetskii, V.; Grabtchikov, A.; Demidovich, A.; Burakevich, V.; Orlovich, V.; Titov, A. Nd:KGW/KGW crystal: Efficient medium for continuous-wave intracavity Raman generation. Appl. Phys. B 2007, 88, 499–501.
  91. Chunaev, D.; Basiev, T.; Konushkin, V.; Papashvili, A.; Karasik, A.Y. Synchronously pumped intracavity YLF–Nd–KGW picosecond Raman lasers and LiF:F–2 amplifiers. Laser Phys. Lett. 2008, 5, 589–592.
  92. Tang, C.-Y.; Zhuang, W.-Z.; Su, K.-W.; Chen, Y.-F. Efficient continuous-wave self-Raman Nd:KGW laser with intracavity cascade emission based on shift of 89 cm−1. IEEE J. Sel. Top. Quantum Electron. 2014, 21, 142–147.
  93. Kisel, V.; Shcherbitsky, V.; Kuleshov, N. Efficient self-frequency Raman conversion in a passively Q-switched diode-pumped Yb:KGd(WO4)2 laser. In Proceedings of the Advanced Solid-State Photonics, San Antonio, TX, USA, 2–5 February 2003; p. 189.
  94. Chang, M.; Zhuang, W.; Su, K.-W.; Yu, Y.; Chen, Y.-F. Efficient continuous-wave self-Raman Yb:KGW laser with a shift of 89 cm−1. Opt. Express 2013, 21, 24590–24598.
  95. Ferreira, M.S.; Wetter, N.U. Yb:KGW self-Raman laser with 89 cm−1 Stokes shift and more than 32% diode-to-Stokes optical efficiency. Opt. Laser Technol. 2020, 121, 105835.
  96. Chen, W.; Inagawa, Y.; Omatsu, T.; Tateda, M.; Takeuchi, N.; Usuki, Y. Diode-pumped, self-stimulating, passively Q-switched Nd3+:PbWO4 Raman laser. Opt. Commun. 2001, 194, 401–407.
  97. Šulc, J.; Jelı, H.; Basiev, T.; Doroschenko, M.; Ivleva, L.; Osiko, V.; Zverev, P. Nd:SrWO4 and Nd:BaWO4 Raman lasers. Opt. Mater. 2007, 30, 195–197.
  98. Jelinkova, H.; Šulc, J.; Basiev, T.; Zverev, P.; Kravtsov, S. Stimulated Raman scattering in Nd:SrWO4. Laser Phys. Lett. 2004, 2, 4.
  99. Liu, J.; Griebner, U.; Petrov, V.; Zhang, H.; Zhang, J.; Wang, J. Efficient continuous-wave and Q-switched operation of a diode-pumped Yb:KLu(WO4)2 laser with self-Raman conversion. Opt. Lett. 2005, 30, 2427–2429.
  100. Cong, Z.; Liu, Z.; Qin, Z.; Zhang, X.; Zhang, H.; Li, J.; Yu, H.; Wang, W. LD-pumped actively Q-switched Nd:KLu(WO4)2 self-Raman laser at 1185 nm. Opt. Laser Technol. 2015, 73, 50–53.
  101. Kaminskii, A.A.; Eichler, H.J.; Ueda, K.-i.; Klassen, N.V.; Redkin, B.S.; Li, L.E.; Findeisen, J.; Jaque, D.; Garcia-Sole, J.; Fernández, J. Properties of Nd3+-doped and undoped tetragonal PbWO4, NaY(WO4)2, CaWO4, and undoped monoclinic ZnWO4 and CdWO4 as laser-active and stimulated Raman scattering-active crystals. Appl. Opt. 1999, 38, 4533–4547.
  102. Major, A.; Cisek, R.; Barzda, V. Development of diode-pumped high average power continuous-wave and ultrashort pulse Yb:KGW lasers for nonlinear microscopy. In Proceedings of the Commercial and Biomedical Applications of Ultrafast Lasers VI, San Jose, CA, USA, 22–25 January 2006; p. 61080Y.
  103. Mateos, X.; Petrov, V.; Aguilo, M.; Sole, R.M.; Gavaldà, J.; Massons, J.; Diaz, F.; Griebner, U. Continuous-wave laser oscillation of Yb3+ in monoclinic KL–u(WO4)2. IEEE J. Quantum Electron. 2004, 40, 1056–1059.
  104. Zhang, J.; Wang, J.; Zhang, H.; Xu, F.; Wang, Z.; Shao, Z.; Zhao, H.; Wang, Y. Growth and diode-pumped CW lasing of Nd:KLu(WO4)2. J. Cryst. Growth 2005, 284, 108–111.
  105. Basiev, T.; Sobol, A.; Voronko, Y.K.; Zverev, P. Spontaneous Raman spectroscopy of tungstate and molybdate crystals for Raman lasers. Opt. Mater. 2000, 15, 205–216.
  106. Basiev, T.T.; Vassiliev, S.V.; Doroshenko, M.E.; Osiko, V.V.; Puzikov, V.M.; Kosmyna, M.B. Laser and self-Raman-laser oscillations of PbMoO4:Nd3+ crystal under laser diode pumping. Opt. Lett. 2006, 31, 65–67.
  107. Basiev, T.; Doroshenko, M.; Ivleva, L.; Voronina, I.; Konjushkin, V.; Osiko, V.; Vasilyev, S. Demonstration of high self-Raman laser performance of a diode-pumpedSrMoO4:Nd3+ crystal. Opt. Lett. 2009, 34, 1102–1104.
  108. Bosenberg, W.; Cheng, L.; Bierlein, J. Optical parametric frequency conversion properties of KTiOAsO4. Appl. Phys. Lett. 1994, 65, 2765–2767.
  109. Edwards, T.; Turnbull, G.; Dunn, M.; Ebrahimzadeh, M.; Colville, F. High-power, continuous-wave, singly resonant, intracavity optical parametric oscillator. Appl. Phys. Lett. 1998, 72, 1527–1529.
  110. Tu, C.S.; Guo, A.; Tao, R.; Katiyar, R.; Guo, R.; Bhalla, A. Temperature dependent Raman scattering in KTiOPO4 and KTiOAsO4 single crystals. J. Appl. Phys. 1996, 79, 3235–3240.
  111. Chen, Y.-F. Stimulated Raman scattering in a potassium titanyl phosphate crystal: Simultaneous self-sum frequency mixing and self-frequency doubling. Opt. Lett. 2005, 30, 400–402.
  112. Zhang, W.; Tao, X.; Zhang, C.; Gao, Z.; Zhang, Y.; Yu, W.; Cheng, X.; Liu, X.; Jiang, M. Bulk growth and characterization of a novel nonlinear optical crystal BaTeMo2O9. Cryst. Growth Des. 2008, 8, 304–307.
  113. Yu, Q.; Gao, Z.; Zhang, S.; Zhang, W.; Wang, S.; Tao, X. Second order nonlinear properties of monoclinic single crystal BaTeMo2O9. J. Appl. Phys. 2012, 111, 013506.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)
Feedback