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Topic Review
Fluorescence-Based Sensors for High-Temperature Monitoring
Fiber-optic high-temperature sensors are gradually replacing traditional electronic sensors due to their small size, resistance to electromagnetic interference, remote detection, multiplexing, and distributed measurement advantages. 
  • 722
  • 17 Aug 2022
Topic Review
InN SAs for Ultrafast Lasers
New fabrication methods are strongly demanded for the development of thin-film saturable absorbers with improved optical properties (absorption band, modulation depth, nonlinear optical response). In this sense, we investigate the performance of indium nitride (InN) epitaxial layers with low residual carrier concentration (<1018 cm^-3), which results in improved performance at telecom wavelengths (1560 nm). These materials have demonstrated a huge modulation depth of 23% and a saturation fluence of 830 uJ/cm2, and a large saturable absorption around -3 x10^4 cm/GW has been observed, attaining an enhanced, nonlinear change in transmittance. We have studied the use of such InN layers as semiconductor saturable absorber mirrors (SESAMs) for an erbium (Er)-doped fiber laser to perform mode-locking generation at 1560 nm. We demonstrate highly stable, ultrashort (134 fs) pulses with an energy of up to 5.6 nJ.a
  • 722
  • 01 Dec 2020
Topic Review
Radiation-Balanced Lasers
Radiation-balanced lasers can provide lasing without detrimental heating of laser medium. This new approach to the design of optically pumped rare-earth (RE)-doped solid-state lasers is provided by balancing the spontaneous and stimulated emission within the laser medium. It is based on the principle of anti-Stokes fluorescence cooling of RE-doped low-phonon solids.
  • 718
  • 13 Sep 2021
Topic Review
Applications of Droplet Microsystems in Optics and Photonics
The micro- and nano-machining techniques applied to solid materials have yielded remarkable success in the semiconductor industry by integrating complex functionalities into microscale devices, thus spearheading the modern electronics revolution. Extending similar miniaturization strategies to process and assemble soft matter for creating multileveled functional structures over various length scales presents significant scientific and practical potential. Soft matter, including liquid crystals (LC), colloids, polymers, and biological substances, exhibits widespread influence across nature, living organisms, daily life, and industry. The biomimetic properties, responsiveness to stimuli, and efficacy in controlled release and sensing make soft matter extensively applicable in biology and chemistry.
  • 703
  • 18 Mar 2024
Topic Review
Polarization Lidar
Traditional lidar techniques mainly rely on the backscattering/echo light intensity and spectrum as information sources. In contrast, polarization lidar (P-lidar) expands the dimensions of detection by utilizing the physical property of polarization. By incorporating parameters such as polarization degree, polarization angle, and ellipticity, P-lidar enhances the richness of physical information obtained from target objects, providing advantages for subsequent information analysis.
  • 702
  • 12 Oct 2023
Topic Review
Holographic Optical Tweezers for Biomedical Applications
Holographic optical tweezers (HOT) is a programmable technique used for manipulation of microsized samples. In combination with computer-generation holography (CGH), a spatial light modulator reshapes the light distribution within the focal area of the optical tweezers. HOT can be used to realize real-time multiple-point manipulation in fluid, and this is useful in biological research.
  • 701
  • 27 Oct 2022
Topic Review Peer Reviewed
High-Power Lasers
High-power lasers play an important role in modern science, industry, and medicine. A significant milestone was reached on 5 December 2022, when Inertial Confinement Nuclear Fusion (ICF) achieved scientific breakeven, releasing more energy than the input laser energy. Additionally, Extreme Ultraviolet Lithography (EUVL) has enabled the development of microchips with 3 nm process nodes, marking a leap in semiconductor technology. These examples, together with the recent achievement of 10 PW (1015 W) laser output, herald remarkable advancements in technology and science. Laser systems are broadly classified based on their operating regimes into two main categories: Continuous Wave (CW) operation, where the laser is continuously pumped and emits a steady beam of light, and the pulsed regime, in which the laser produces single or multiple pulses at various repetition rates. This review will primarily focus on pulsed laser systems, exploring their various types and recent technological advancements.
  • 698
  • 09 Aug 2024
Topic Review
Lead Halide Perovskites Opto-Electronic Devices
In Lead Halide Perovskites Opto-Electronic Devices, we will discuss the development in the LHP-based functional devices in recent years. After a brief presentation of the LHP's properties, we will focus on the functional devices including lasers, photodetectors, and modulators. Then the fabrication of the LHP-based devices will be presented, which is followed by the summary and outlook.
  • 695
  • 29 Apr 2021
Topic Review
Ultrafast Laser in Orthopedic Surgery
The potential of ultrafast lasers (pico- to femtosecond) in orthopedics-related procedures has been studied extensively for clinical adoption. As compared to conventional laser systems with continuous wave or longer wave pulse, ultrafast lasers provide advantages such as higher precision and minimal collateral thermal damages. Translation to surgical applications in the clinic has been restrained by limitations of material removal rate and pulse average power, whereas the use in surface texturing of implants has become more refined to greatly improve bioactivation and osteointegration within bone matrices.
  • 695
  • 07 May 2022
Topic Review
Optical Polarization-Based Measurement for Peptides and Amino Acids
Polarization-based optical measurement methods are very useful in the analysis of the molecular orientations of materials, and, thus, these methods are implemented in numerous material-science studies, including into the characterization of amino acids’ (SAPA)  micro- and nanostructures.
  • 687
  • 21 Mar 2022
Topic Review
Intensity-Modulated Polymer Optical Fiber-Based Refractive Index Sensor
The simple and highly sensitive measurement of the refractive index (RI) of liquids is critical for designing the optical instruments and important in biochemical sensing applications. Intensity modulation-based polymer optical fiber (POF) RI sensors have a lot of advantages including low cost, easy fabrication and operation, good flexibility, and working in the visible wavelength.
  • 683
  • 25 Apr 2022
Topic Review
Bio-Photonic Cavities
An eco-friendly approach to usual optical cavities, in which an electromagnetic radiation can release energy to matter by interacting with its molecular or atomic structure. Based on bio-inspired and biodegradable meta-surfaces, able to behave as a resonator for light, their optical response can be engineered at will to accomplish a particular optical task.  
  • 678
  • 24 Nov 2021
Topic Review
Fabrication of Semiconductor Optical Fibers
Because of their thermal and mechanical mismatch with typical glass materials, the fabrication of optical fibers from semiconductors is a considerable challenge for the field of materials science. As a result, the platform for optical fibers has been restricted to materials that are consistent with the typical fiber drawing techniques for an extended period. In 2006, a chemical deposition approach was used to create the initial example of a crystalline semiconductor optical fiber. As a result of this endeavor, different methods have been utilized in the fabrication of semiconductor optical fibers. Each of these methods has its own set of benefits and drawbacks. Since there have been no standardized techniques for fabricating these fibers, their production is relatively costly.
  • 675
  • 31 Oct 2022
Topic Review
Materials and Applications of Smart Contact Lenses
Smart contact lenses (SCLs) have found applications in the continuous monitoring of ocular parameters, encompassing both physical characteristics, such as pressure and temperature, as well as chemical markers like glucose levels, protein content, and pH. These physiological indicators are intricately linked to human well-being, with noteworthy implications for health.
  • 658
  • 31 Oct 2023
Biography
Waheed Arian
Waheed Arian (born 5 August 1983) is a British doctor and radiologist, born in Afghanistan, who founded a telemedicine charity called Arian Teleheal. The charity enables doctors in conflict zones and low resource countries to use their smartphones to receive advice from volunteer specialists in the UK, Canada, the US and other countries. Arian has won several international awards for his achieve
  • 651
  • 12 Dec 2022
Topic Review
Precise Optical Modulation
Optoelectronic devices which play important roles in high-speed optical fiber networks can offer effective measurement methods for optoelectronic devices including optical modulators and photodetectors. Precise optical signal modulation is required for measurement applications.
  • 647
  • 19 May 2021
Topic Review
Optical Parametric Oscillators and Raman Lasers
Optical parametric oscillators (OPOs) and Raman lasers are two nonlinear-based laser technologies that extend the spectral range of conventional inversion lasers. Power and brightness scaling of lasers are significant for many applications in industry, medicine, and defense. Considerable advances have been made to enhance the power and brightness of inversion lasers.
  • 642
  • 30 Jan 2022
Topic Review
Mesoscale Dielectric Particles: Unusual Optical Effects
Mesoscale dielectric particles are mesostructures comprising both wavelength-scaled (i.e. dimensions comparable to wavelength) particles and particle chains or arrays. These particles are made of low loss dielectric materials having relatively low refractive index, namely the refractive index less than two. The main unusual optical effects in such structures are discussed below.
  • 632
  • 01 Jan 2022
Topic Review
On Ghost Imaging Studies for Information Optical Imaging
To understand, study, and optimize optical imaging systems from the information-theoretic viewpoint has been an important research subfield. However, the "direct point-to-point" image information acquisition mode of traditional optical imaging is lacking in "Coding-decoding" operation on the image information, and limits the development of further imaging capabilities. On the other hand, ghost imaging (GI) systems, combined with modern light-field modulation and digital photoelectric detection technologies, behave more in line with the modulation–demodulation information transmission mode compared to traditional optical imaging. This puts forward imperative demands and challenges for understanding and optimizing ghost imaging systems from the viewpoint of information theory, as well as bringing more development opportunities for the research field of information optical imaging. Here, several specific GI systems and studies with various extended imaging capabilities will be briefly reviewed. 
  • 627
  • 14 Nov 2022
Topic Review
Double-Blind FROG
Double-Blind FROG is a method for simultaneously measuring two unknown ultrashort laser pulses. Well established ultrafast measurement techniques like Frequency-Resolved Optical Gating (FROG) and its simplified version GRENOUILLE can only measure one unknown ultrashort laser pulse at a time. Another version of FROG, called cross-correlation FROG (XFROG), also measures only one pulse, but it involves two pulses: a known reference pulse and the unknown pulse to be measured. In modern optics experiments, ultrashort laser pulses have been used in a great variety of engineering application and scientific research, for example, biomedical engineering, material science, nonlinear spectroscopy, ultrafast chemistry, etc. Often, these experiments involve using two potentially different input laser pulses, for example, Raman spectroscopy, two-color pump-probe experiments, and non-degenerate four-wave mixing. In many situations, an output pulse is generated by a nonlinear optical process, such as harmonic generation, continuum generation, or optical parametric oscillation. In all such cases, measuring more than one pulse simultaneously is required to completely characterize the experiment and understand its results in order to eventually understand the underlying science of the process under study. Thus a measurement device capable of measuring two pulses simultaneously is highly desired.
  • 624
  • 20 Oct 2022
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