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Electro-optic
Electro–optics is a branch of electrical engineering, electronic engineering, materials science, and material physics involving components, electronic devices such as lasers, laser diodes, LEDs, waveguides, etc. which operate by the propagation and interaction of light with various tailored materials. It is closely related to photonics, the branch of optics that involves the application of the generation of photons. It is not only concerned with the " electro–optic effect", since it deals with the interaction between the electromagnetic (optical) and the electrical ( electronic) states of materials. Electro-optical devices The electro-optic effect is a change in the optical properties of an optically active material in response to changes in an electric field. This interaction usually results in a change in the birefringence Birefringence, also called double refraction, is the optical property of a material having a refractive index that depends on the polarizat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electro–optic Effect
An electro–optic effect is a change in the optical properties of a material in response to an electric field that varies slowly compared with the frequency of light. The term encompasses a number of distinct phenomena, which can be subdivided into * a) change of the absorption ** Electroabsorption: general change of the absorption constants ** Franz–Keldysh effect: change in the absorption shown in some bulk semiconductors ** Quantum-confined Stark effect: change in the absorption in some semiconductor quantum wells ** Electrochromic effect: creation of an absorption band at some wavelengths, which gives rise to a change in colour * b) change of the refractive index and permittivity ** Pockels effect (or linear electro-optic effect): change in the refractive index linearly proportional to the electric field. Only certain crystalline solids show the Pockels effect, as it requires lack of inversion symmetry ** Kerr effect (or quadratic electro-optic effect, QEO effect): chan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pockels Effect
In optics, the Pockels effect, or Pockels electro-optic effect, is a directionally-dependent linear variation in the refractive index of an optical medium that occurs in response to the application of an electric field. It is named after the German physicist Friedrich Carl Alwin Pockels, who studied the effect in 1893. The non-linear counterpart, the Kerr effect, causes changes in the refractive index at a rate proportional to the square of the applied electric field. In optical media, the Pockels effect causes changes in birefringence that vary in proportion to the strength of the applied electric field. The Pockels effect occurs in crystals that lack inversion symmetry, such as monopotassium phosphate (, abbr. KDP), potassium dideuterium phosphate (, abbr. KD*P or DKDP), lithium niobate (), beta-barium borate (BBO), barium titanate (BTO) and in other non-centrosymmetric media such as electric-field poled polymers or glasses. The Pockels effect has been elucidated through ext ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kerr Cell
The Kerr effect, also called the quadratic electro-optic (QEO) effect, is a change in the refractive index of a material in response to an applied electric field. The Kerr effect is distinct from the Pockels effect in that the induced index change for the Kerr effect is directly proportional to the ''square'' of the electric field instead of varying linearly with it. All materials show a Kerr effect, but certain liquids display it more strongly than others. The Kerr effect was discovered in 1875 by Scottish physicist John Kerr. Two special cases of the Kerr effect are normally considered, these being the Kerr electro-optic effect, or DC Kerr effect, and the optical Kerr effect, or AC Kerr effect. Kerr electro-optic effect The Kerr electro-optic effect, or DC Kerr effect, is the special case in which a slowly varying external electric field is applied by, for instance, a voltage on electrodes across the sample material. Under this influence, the sample becomes birefringent, wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electro-optic Effect
Electro–optics is a branch of electrical engineering, electronic engineering, materials science, and material physics involving components, electronic devices such as lasers, laser diodes, LEDs, waveguides, etc. which operate by the propagation and interaction of light with various tailored materials. It is closely related to photonics, the branch of optics that involves the application of the generation of photons. It is not only concerned with the " electro–optic effect", since it deals with the interaction between the electromagnetic (optical) and the electrical ( electronic) states of materials. Electro-optical devices The electro-optic effect is a change in the optical properties of an optically active material in response to changes in an electric field. This interaction usually results in a change in the birefringence Birefringence, also called double refraction, is the optical property of a material having a refractive index that depends on the polarizatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoferroelectric Imaging
Photoferroelectric imaging is the process of storing an image onto a piece of ferroelectric material by the aid of an applied electric pulse. Stored images are nonvolatile and selectively erasable. Photoferroelectric image storage devices have the advantage of being "extremely simple and easy to fabricate". Photoferroelectric imaging uses a ferroelectric material's photosensitivity in conjunction with its ferroelectric properties. One type of medium which has been used for photoferroelectric imaging is lead lanthanum zirconate titanate (PLZT) ceramics, which exhibit a good combination of properties for imaging: large electro-optic coefficients, high intrinsic and extrinsic photosensitivities, and nonvolatile memory. Process A description of a photoferroelectric imaging process (using PLZT material) is given in the ''McGraw-Hill Concise Encyclopedia of Science and Technology''. In that process, a thin flat plate of transparent, optically polished PLZT material (around 0.25mm thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photonics
Photonics is a branch of optics that involves the application of generation, detection, and manipulation of light in the form of photons through emission, transmission, modulation, signal processing, switching, amplification, and sensing. Even though photonics is a commonly used term, there is no widespread agreement on a clear definition of the term or on the difference between photonics and related fields, such as optics. Photonics is closely related to quantum electronics, where quantum electronics deals with the theoretical part of it while photonics deal with its engineering applications. Though covering all light's technical applications over the whole spectrum, most photonic applications are in the range of visible and near-infrared light. The term ''photonics'' developed as an outgrowth of the first practical semiconductor light emitters invented in the early 1960s and optical fibers developed in the 1970s. History The word 'Photonics' is derived from the Greek w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Engineering
Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems that use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the latter half of the 19th century after the commercialization of the electric telegraph, the telephone, and electrical power generation, distribution, and use. Electrical engineering is divided into a wide range of different fields, including computer engineering, systems engineering, power engineering, telecommunications, radio-frequency engineering, signal processing, instrumentation, photovoltaic cells, electronics, and optics and photonics. Many of these disciplines overlap with other engineering branches, spanning a huge number of specializations including hardware engineering, power electronics, Electromagnetism, electromagnetics and waves, microwave engineering, nanotechnology, electrochemistry, renewable energies, mechatronics/control ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birefringence
Birefringence, also called double refraction, is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. These optically anisotropic materials are described as birefringent or birefractive. The birefringence is often quantified as the maximum difference between refractive indices exhibited by the material. Crystals with non-cubic crystal structures are often birefringent, as are plastics under mechanical stress. Birefringence is responsible for the phenomenon of double refraction whereby a ray of light, when incident upon a birefringent material, is split by polarization into two rays taking slightly different paths. This effect was first described by Danish scientist Rasmus Bartholin in 1669, who observed it in Iceland spar (calcite) crystals which have one of the strongest birefringences. In the 19th century Augustin-Jean Fresnel described the phenomenon in terms of polarization, understanding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Light is a type of electromagnetic radiation, and other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties. Most optical phenomena can be accounted for by using the classical electromagnetic description of light, however complete electromagnetic descriptions of light are often difficult to apply in practice. Practical optics is usually done using simplified models. The most common of these, geometric optics, treats light as a collection of rays that travel in straight lines and bend when they pass through or reflect from surfaces. Physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word ''laser'' originated as an acronym for light amplification by stimulated emission of radiation. The first laser was built in 1960 by Theodore Maiman at Hughes Research Laboratories, based on theoretical work by Charles H. Townes and Arthur Leonard Schawlow and the optical amplifier patented by Gordon Gould. A laser differs from other sources of light in that it emits light that is coherence (physics), ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling uses such as optical communication, laser cutting, and Photolithography#Light sources, lithography. It also allows a laser beam to stay narrow over great distances (collimated light, collimation), used in laser pointers, lidar, and free-space optical communication. Lasers can also have high temporal coherence, which permits them to emit light ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
