A Volume Bragg Grating (VBG) laser diode is a type of laser diode that uses Bragg grating to achieve high spectral purity and wavelength stabilization. Volume Bragg Grating is a transparent medium that exhibits a periodic variation in its refractive index and provides narrow linewidth for laser diodes. It is used for pumping some solid-state lasers in which the laser crystal exhibits efficien...read more

A Distributed Bragg Reflector (DBR) Laser is a semiconductor laser with a p-n junction as an active medium and contains one or two Bragg reflectors on each side of the active region. Bragg reflectors are gratings that act as mirrors or end reflectors with reflectivity optimized at a particular wavelength and it narrows the laser linewidth. In DBR, the grating is outside the active region where no ...read more

Quantum Efficiency Fill Factor (QEFF) is a combination of quantum efficiency (QE) and fill factor (FF), which are the key parameters that determine the efficiency of the Short-Wave Infrared (SWIR) sensor that is used to detect light in the near-infrared spectrum. By converting more light into electrical energy and using more of the electrical energy generated, these two parameters play a crucial r...read more

Micro-optics and Diffractive optics are both subfields of optics that deal with the manipulation of light at a small scale. These optical elements are usually macroscopic planar structures, built by sophisticated numerical methods based on diffraction theory, with sizes ranging from a few wavelengths to a few tens of microns.Micro-opticsMicro-optics are often used to create optical systems that ar...read more

An Erbium-Doped Fiber Amplifier (EDFA) is a device that amplifies weak input optical signals without converting them into electrical signals. An optical amplifier is a device that amplifies the intensity of optical signals traveling through fiber optic cables without converting them into electrical signals. EDFAs were invented in the mid-1980s by Dr. David Payne and his team at the University of S...read more

Bragg's Law is a fundamental principle in physics that explains how X-rays and other types of electromagnetic radiation can be used to determine the structure of crystals. Bragg’s Law is used to calculate the angles at which X-rays are diffracted by a crystal to determine the positions of atoms within the crystal lattice. This law was put forward by Sir William Lawrence Bragg and his fat...read more

Amplified Spontaneous Emission is the spontaneous emission exhibited by the pumped laser gain medium even when there is no light signal being amplified. Spontaneous emission is a process in which an atom in an excited state spontaneously emits a photon without any external stimulation. This process occurs randomly and without any specific direction or coherence. However, in the presence of a gain ...read more

The electromagnetic spectrum is defined as the distribution of a number of electromagnetic waves as a function of wavelength, frequency, or wave number. The EM spectrum exhibits both wave-like and particle-like properties. The behaviour of the shortest wavelengths is dominated by wave characteristics, whereas the behaviour of short-wavelength X-rays and gamma rays is dominated by photon aspects, y...read more

Birefringence, also known as double refraction, is a phenomenon that occurs when light passes through certain materials and is split into two rays, each with a different index of refraction. This effect was first discovered by the Danish scientist Rasmus Bartholin in the 17th century, and it has since been studied extensively in the field of optics.Light is an electromagnetic wave that contains el...read more

In optics, the ABCD law is a fundamental principle used to describe the behavior of light rays as they pass through optical systems. This law provides a simple and powerful way to analyze the propagation of light through complex optical systems, such as lenses, mirrors, and other optical components. The ABCD law is essential for designing and optimizing optical systems used in a variety of ap...read more

A Quantum well laser is a type of semiconductor laser where the thickness of the active region is very narrow. The thickness of the active region determines the wavelength of the light emitted by the laser. These lasers have active regions of a thickness of about 100 Å. The emission wavelength is typically between 700 nm and 1600 nm for these lasers. The Pulse duration of a light pulse ...read more

A Phototransistor is a kind of transistor that is sensitive to light. It comprises of a photodiode & a transistor which is used to detect light and convert it into an electrical signal. The phototransistor was invented by John Northrup Shive in 1950 at Bell Telephone Laboratories. Its operation is based on the concept of the photoelectric effect. That is, when light is incident on a surface, t...read more

X-ray lasers are lasers that generate bright laser beams at discrete wavelengths ranging from 3.56 nm to 46.9 nm. A traditional gain medium cannot be used in x-ray lasers. They use a highly ionized plasma region created in a capillary discharge as the active medium and the plasma is created with a laser beam or with an electrical discharge. Mirrors that can reflect x-rays with normal incidence are...read more

A Fresnel zone plate is a diffractive element consisting of multiple concentric rings that alternate between transparent and opaque regions used to focus light or other wave-like objects. They were initially described in the 19th century by a French scientist named Augustin-Jean Fresnel, hence the name "Fresnel zone plates". Zone plates are used as imaging lenses with a single focus in p...read more

Blackbody radiation is electromagnetic thermal radiation that radiates inside or surrounding a body that is in thermal equilibrium with its surroundings. Thermal equilibrium is a state in which two or more systems in thermal contact have reached a constant temperature and no heat is exchanged between them. In other words, in thermal equilibrium, the temperature of the systems is the same, and ther...read more