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Topic Review
Classification of Continuous-Variable Quantum Key Distribution Protocols
Quantum communications, in general, and quantum key distribution (QKD) as one of the internal directions, in particular, are some of the most actively developing areas of quantum technologies. QKD allows one to send a secure key between several legitimate users connected by so-called quantum and classical channels. Theoretically, the security of QKD is based on the principles of quantum mechanics, which guarantees security against any unforeseen technological developments, for example, in the field of quantum computing.
  • 1.7K
  • 14 Feb 2023
Topic Review
Fourier Lightfield Microscope
Fourier lightfield microscopy (FLMic) is a technique aimed to capture and process 3D information of microscopic samples. Due to its optical design, FLMic has the inherent capacity of capturing a collection of orthographic perspectives of samples in a single shot. Consequently, FLMic is especially suited for capturing and processing 3D images of dynamic processes, being potentially addressed for real-time applications in both life and material sciences.
  • 1.7K
  • 10 Mar 2022
Biography
William Happer
William "Will" Happer (born July 27, 1939[1]) is an American physicist who has specialized in the study of atomic physics, optics and spectroscopy.[2] He is the Cyrus Fogg Brackett[3] Professor of Physics, Emeritus, at Princeton University,[2] and a long-term member of the JASON advisory group,[1] where he pioneered the development of adaptive optics. From 1991 to 1993, Happer served as director
  • 1.6K
  • 15 Nov 2022
Topic Review
Food Fraud Detection by LPAS
Economically motivated adulterations of food, in general, and spices, in particular, are an emerging threat to world health. Reliable techniques for the rapid screening of counterfeited ingredients in the supply chain need further development. Building on the experience gained with CO2 lasers, the Diagnostic and Metrology Laboratory of ENEA realized a compact and user-friendly photoacoustic laser system for food fraud detection, based on a quantum cascade laser. The sensor has been challenged with saffron adulteration. Multivariate data analysis tools indicated that the photoacoustic laser system was able to detect adulterants at mass ratios of 2% in less than two minutes.
  • 1.6K
  • 28 Jun 2021
Topic Review
Video Feedback
Video feedback is the process that starts and continues when a video camera is pointed at its own playback video monitor. The loop delay from camera to display back to camera is at least one video frame time, due to the input and output scanning processes; it can be more if there is more processing in the loop.
  • 1.6K
  • 02 Dec 2022
Topic Review
Mid-Infrared Femtosecond Laser Based on Difference Frequency Generation
The mid-infrared (MIR) spectral region is known as the “molecular fingerprint region”, and almost every kind of gas molecule shows a unique and strong absorption characteristic within that region. The MIR ultrashort pulsed lasers can be widely used in gas detection, cancer diagnosis, pollutant monitoring, food quality control, and other aspects since they own much broader spectral ranges than ultrafast lasers in the visible and near-infrared region. There have been different techniques for the generation of ultrashort pulses in the MIR region of 2-5 µm. However, for the MIR ultrashort pulses generation at wavelengths longer than 5 µm or even 8 µm, difference frequency generation (DFG) is the primary technique.
  • 1.5K
  • 06 Jun 2022
Topic Review
Continuous-Wave THz Imaging
Terahertz (THz) spectroscopy and imaging technology have seen significant developments in the fields of biology, medical diagnosis, food safety, and nondestructive testing. Label-free diagnosis of malignant tumours has been obtained and also achieved significant development in THz biomedical imaging.
  • 1.5K
  • 07 Jan 2021
Topic Review
Application of Two-Dimensional Materials towards CMOS-Integrated Gas Sensors
The semiconductor metal oxide (SMO)-based gas sensor, considered the current workhorse of semiconductor-based chemiresistive gas sensor technologies, requires high temperatures to initiate the surface reactions which result in the sensing response, making it difficult to fabricate and prone to high mechanical instability. Therefore, alternatives at lower temperatures are desired, where 2D materials seem to hold the most promise. Even at ambient temperature, their sensitivity is extraordinarily large due to their extremely high surface-to-volume ratio. However, some ongoing issues still need to be resolved before gas sensors based on 2D materials can be widely used and commercialized. The alternative room temperature solutions involve optical signals, either by designing an nondispersive infrared (NDIR) sensor based on the Beer-Lambert law or by introducing an additional UV illumination to SMO sensors. In both cases, complementary metal oxide semiconductor (CMOS) integration is not feasible, which is why continued interest in 2D-material-based gas sensors persists.
  • 1.5K
  • 02 Dec 2022
Topic Review
Near- and Mird-Infrared Spectroscopy
Given the exquisite capability of direct, non-destructive label-free sensing of molecular transitions, IR spectroscopy has become a ubiquitous and versatile analytical tool. IR application scenarios range from industrial manufacturing processes, surveillance tasks and environmental monitoring to elaborate evaluation of (bio)medical samples. Given recent developments in associated fields, IR spectroscopic devices increasingly evolve into reliable and robust tools for quality control purposes, for rapid analysis within at-line, in-line or on-line processes, and even for bed-side monitoring of patient health indicators. 
  • 1.5K
  • 03 Aug 2022
Topic Review
Integrated OPAs for Beam Forming/Steering
Integrated optical phased arrays (OPAs) can be used for beam shaping and steering with a small footprint, lightweight, high mechanical stability, low price, and high-yield, benefiting from the mature CMOS-compatible fabrication. 
  • 1.4K
  • 18 Jun 2021
Topic Review
The Structural and Optical Properties of Carotenoid Compounds
Carotenoid compounds are ubiquitous in nature, providing the characteristic colouring of many algae, bacteria, fruits and vegetables. They are a critical component of the human diet and play a key role in human nutrition, health and disease. 
  • 1.4K
  • 09 Jan 2023
Topic Review
Allying Meta-Structures with Diverse Optical Waveguides for Integrated-Photonics
Recent years have witnessed tremendous interest in synergizing various functional subwavelength structures into diverse optical waveguide platforms to enable versatile photonic meta-devices. The advancement of meta-waveguides not only extends meta-optics into the manipulation of guided wave, but may also reshape the landscapes of photonic integrated circuits and massive emergent applications. A recent review paper outlined latest progress on meta-waveguides-based photonics devices and systems. Both forward and inverse designed scenarios are cataloged showcasing vibrant opportunities.
  • 1.3K
  • 13 Dec 2021
Topic Review
Near-Infrared Graphene/Silicon Photodetectors
In recent years, graphene has attracted much interest due to its unique properties of flexibility, strong light-matter interaction, high carrier mobility and broadband absorption. In addition, graphene can be deposited on many substrates including silicon with which is able to form Schottky junctions, opening the path to the realization of near-infrared photodetectors based on the internal photoemission effect where graphene plays the role of the metal.
  • 1.3K
  • 29 Oct 2020
Topic Review
A Specialty Fiber for Distributed Acoustic Sensing Technology
Specialty fibers have introduced new levels of flexibility and variability in distributed fiber sensing applications. In particular, distributed acoustic sensing (DAS) systems utilized the unique functions of specialty fibers to achieve performance enhancements in various distributed sensing applications. 
  • 1.3K
  • 28 Apr 2022
Biography
Chandrasekhara Venkata Raman
Chandrasekhara Venkata Raman, born on November 7, 1888, and passed away on November 21, 1970, was a distinguished Indian physicist renowned for his contributions to the study of light scattering. Alongside his student K. S. Krishnan, he developed a spectrograph and made a groundbreaking discovery – the modification of light scattering when it passes through a transparent material. This phenome
  • 1.2K
  • 17 Feb 2024
Topic Review
Quantum Rayleigh Annihilation of Entangled Photons and Quantum Local Realism
The interpretation of published experimental results intended to prove the existence of a quantum phenomenon of non-locality involving photonic entangled states did not take into consideration the existence of the quantum Rayleigh conversion of photons in dielectric media. This phenomenon leads to the existence of high levels of correlations between two independent photonic and linearly polarized quantum states generated after the entangled photons have been absorbed through the quantum Rayleigh conversion. Both pure and mixed individual states of polarization result in expressions normally associated with entangled photonic states, providing support for the view that the physical reality of quantum non-locality is highly questionable.
  • 1.2K
  • 28 Oct 2020
Topic Review
3D-Printed Silica Glass
Glass technologies for 3D printing can be divided into several categories according to the printing method and the form of pre-treatment for the raw materials. These categories include powder-based, photopolymerization-based, and material extrusion-based 3D printing technology. Among them, fused deposition modeling (FDM), based on material extrusion (MEX), and selective laser sintering/melting (SLS/SLM), based on powder, usually require strict processing conditions and are therefore less suitable for laboratory processing. The most promising processing technologies are stereolithography (SLA), digital light processing (DLP), two-photon polymerization (TPP), sheet lamination (SL), which is based on photopolymerization, and DIW, based on MEX.
  • 1.2K
  • 28 Feb 2022
Topic Review
Nanomaterials for Optical Coherence Tomography in Nanodentistry
There is already a societal awareness of the growing impact of nanoscience and nanotechnology, with nanomaterials (with at least one dimension less than 100 nm) now incorporated in items as diverse as mobile phones, clothes or dentifrices. In the healthcare area, nanoparticles of biocompatible materials have already been used for cancer treatment or bioimaging enhancement. Nanotechnology in dentistry, or nanodentistry, has already found some developments in dental nanomaterials for caries management, restorative dentistry and orthodontic adhesives. 
  • 1.1K
  • 01 Mar 2022
Topic Review
Biosensing Using SERS Active Gold Nanostructures
Surface-enhanced Raman spectroscopy (SERS) has become a powerful tool for biosensing applications owing to its fingerprint recognition, high sensitivity, multiplex detection, and biocompatibility. This review provides an overview of the most significant aspects of SERS for biomedical and biosensing applications. 
  • 1.1K
  • 01 Nov 2021
Biography
Md. Anowar Hossain
Engr. Md. Anowar Hossain is a specialized textile engineer (textile coloration & technical textiles), consultant (textile engineering), Professor (textile engineering), color philosopher, scientist, motivational speaker and a writer.                                                                                          Figure 1. Sketch of academi
  • 1.1K
  • 15 Sep 2023
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