|
Optoelectronics
Optoelectronics (or optronics) is the study and application of electronic devices and systems that find, detect and control light, usually considered a sub-field of photonics. In this context, ''light'' often includes invisible forms of radiation such as gamma rays, X-rays, ultraviolet and infrared, in addition to visible light. Optoelectronic devices are electrical-to-optical or optical-to-electrical transducers, or instruments that use such devices in their operation. '' Electro-optics'' is often erroneously used as a synonym, but is a wider branch of physics that concerns all interactions between light and electric fields, regardless of whether they form part of an electronic device. Optoelectronics is based on the quantum mechanical effects of light on electronic materials, especially semiconductors, sometimes in the presence of electric fields. * Photoelectric or photovoltaic effect, used in: ** photodiodes (including solar cells) ** phototransistors ** photomult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integrated Optical Circuit
A photonic integrated circuit (PIC) or integrated optical circuit is a microchip containing two or more photonic components that form a functioning circuit. This technology detects, generates, transports, and processes light. Photonic integrated circuits use photons (or particles of light) as opposed to electrons that are used by integrated circuit, electronic integrated circuits. The major difference between the two is that a photonic integrated circuit provides functions for information signals imposed on optical wavelengths typically in the visible spectrum or near-infrared (850–1650 nm). One of the most commercially utilized material platforms for photonic integrated circuits is indium phosphide (InP), which allows for the integration of various optically active and passive functions on the same chip. Initial examples of photonic integrated circuits were simple 2-section distributed Bragg reflector (DBR) lasers, consisting of two independently controlled device sections� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Sensor
Photodetectors, also called photosensors, are devices that detect light or other forms of electromagnetic radiation and convert it into an electrical signal. They are essential in a wide range of applications, from digital imaging and optical communication to scientific research and industrial automation. Photodetectors can be classified by their mechanism of detection, such as the photoelectric effect, photochemical reactions, or thermal effects, or by performance metrics like spectral response. Common types include photodiodes, phototransistors, and photomultiplier tubes, each suited to specific uses. Solar cells, which convert light into electricity, are also a type of photodetector. This article explores the principles behind photodetectors, their various types, applications, and recent advancements in the field. History The development of photodetectors began with the discovery of the photoelectric effect by Heinrich Hertz in 1887, later explained by Albert Einstein i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photovoltaic
Photovoltaics (PV) is the conversion of light into electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry. The photovoltaic effect is commercially used for electricity generation and as photosensors. A photovoltaic system employs solar modules, each comprising a number of solar cells, which generate electrical power. PV installations may be ground-mounted, rooftop-mounted, wall-mounted or floating. The mount may be fixed or use a solar tracker to follow the sun across the sky. Photovoltaic technology helps to mitigate climate change because it emits much less carbon dioxide than fossil fuels. Solar PV has specific advantages as an energy source: once installed, its operation does not generate any pollution or any greenhouse gas emissions; it shows scalability in respect of power needs and silicon has large availability in the Earth's crust, although other materials required in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light-emitting Diode
A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresponding to the energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device. Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared (IR) light. Infrared LEDs are used in remote-control circuits, such as those used with a wide variety of consumer electronics. The first visible-light LEDs were of low intensity and limited to red. Early LEDs were often used as indicator lamps, replacing small incandescent bulbs, and in seven-segment displays. Later developments produced LEDs available in visible, ultraviolet (U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiative Recombination
In solid-state physics of semiconductors, carrier generation and carrier recombination are processes by which mobile charge carriers (electrons and electron holes) are created and eliminated. Carrier generation and recombination processes are fundamental to the operation of many optoelectronic semiconductor devices, such as photodiodes, light-emitting diodes and laser diodes. They are also critical to a full analysis of p-n junction devices such as bipolar junction transistors and p-n junction diodes. The electron–hole pair is the fundamental unit of generation and recombination in inorganic semiconductors, corresponding to an electron transitioning between the valence band and the conduction band where generation of an electron is a transition from the valence band to the conduction band and recombination leads to a reverse transition. Overview Like other solids, semiconductor materials have an electronic band structure determined by the crystal properties of the material. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoresistor
A photoresistor (also known as a light-dependent resistor, LDR, or photo-conductive cell) is a passive component that decreases in resistance as a result of increasing luminosity (light) on its sensitive surface, in other words, it exhibits photoconductivity. A photoresistor can be used in light-sensitive detector circuits and light-activated and dark-activated switching circuits acting as a semiconductor resistance. In the dark, a photoresistor can have a resistance as high as several megaohms (MΩ), while in the light, it can have a resistance as low as a few hundred ohms. If incident light on a photoresistor exceeds a certain frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band. The resulting free electrons (and their hole partners) conduct electricity, thereby lowering resistance. The resistance range and sensitivity of a photoresistor can substantially differ among dissimilar devices. Moreover, unique photor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optoisolator
An opto-isolator (also called an optocoupler, photocoupler, or optical isolator) is an electronic component that transfers electrical Signal, signals between two isolated circuits by using light. Opto-isolators prevent high voltages from affecting the system receiving the signal.Lee et al., p. 2. Commercially available opto-isolators withstand input-to-output voltages up to 10 Volt, kVHasse, p. 145. and voltage transients with speeds up to 25 kV/microsecond, μs.Joffe and Kai-Sang Lock, p. 279. A common type of opto-isolator consists of an Light emitting diode, LED and a phototransistor in the same opaque package. Other types of source-sensor combinations include LED-photodiode, LED-thyristor#Photothyristors, LASCR, and lamp (electrical component), lamp-photoresistor pairs. Usually opto-isolators transfer digital (on-off) signals and can act as an electronic switch, but some techniques allow them to be used with analog signals. History The value of optically coupling a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
