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Electromagnetically Induced Transparency
Electromagnetically induced transparency (EIT) is a coherent optical nonlinearity which renders a medium transparent within a narrow spectral range around an absorption line. Extreme dispersion is also created within this transparency "window" which leads to "slow light", described below. It is in essence a quantum interference effect that permits the propagation of light through an otherwise opaque atomic medium. Observation of EIT involves two optical fields (highly coherent light sources, such as lasers) which are tuned to interact with three quantum states of a material. The "probe" field is tuned near resonance between two of the states and measures the absorption spectrum of the transition. A much stronger "coupling" field is tuned near resonance at a different transition. If the states are selected properly, the presence of the coupling field will create a spectral "window" of transparency which will be detected by the probe. The coupling laser is sometimes referred t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIT Spectrum
EIT may refer to: Education and research institutes * Eastern Institute of Technology, in New Zealand * Emirates Institute of Technology, now Emirates College of Technology * Engineering Institute of Technology, in Perth, Australia * Eritrea Institute of Technology, in Abardae Mai Nefhi, Eritrea * European Institute of Innovation and Technology, headquartered in Budapest, Hungary Science * Electrical impedance tomography * Electromagnetically induced transparency * Extended irreversible thermodynamics * Extreme ultraviolet Imaging Telescope Other uses * Eitiep language * Engineer in Training, professional certification level * Enhanced interrogation techniques * Everything Is Terrible!, a video blog * Economies-in-transition, defined by the Kyoto Protocol The Kyoto Protocol was an international treaty which extended the 1992 United Nations Framework Convention on Climate Change (UNFCCC) that commits state parties to reduce greenhouse gas emissions, based on the scient ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIT Schemes
EIT may refer to: Education and research institutes * Eastern Institute of Technology, in New Zealand * Emirates Institute of Technology, now Emirates College of Technology * Engineering Institute of Technology, in Perth, Australia * Eritrea Institute of Technology, in Abardae Mai Nefhi, Eritrea * European Institute of Innovation and Technology, headquartered in Budapest, Hungary Science * Electrical impedance tomography * Electromagnetically induced transparency * Extended irreversible thermodynamics * Extreme ultraviolet Imaging Telescope Other uses * Eitiep language * Engineer in Training, professional certification level * Enhanced interrogation techniques * Everything Is Terrible!, a video blog * Economies-in-transition, defined by the Kyoto Protocol The Kyoto Protocol was an international treaty which extended the 1992 United Nations Framework Convention on Climate Change (UNFCCC) that commits state parties to reduce greenhouse gas emissions, based on the scient ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamiltonian (quantum Mechanics)
Hamiltonian may refer to: * Hamiltonian mechanics, a function that represents the total energy of a system * Hamiltonian (quantum mechanics), an operator corresponding to the total energy of that system ** Dyall Hamiltonian, a modified Hamiltonian with two-electron nature ** Molecular Hamiltonian, the Hamiltonian operator representing the energy of the electrons and nuclei in a molecule * Hamiltonian (control theory), a function used to solve a problem of optimal control for a dynamical system * Hamiltonian path, a path in a graph that visits each vertex exactly once * Hamiltonian group, a non-abelian group the subgroups of which are all normal * Hamiltonian economic program, the economic policies advocated by Alexander Hamilton, the first United States Secretary of the Treasury See also * Alexander Hamilton (1755 or 1757–1804), American statesman and one of the Founding Fathers of the US * Hamilton (other) Hamilton may refer to: People * Hamilton (name), a common ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Dressed State
In the fields of atomic, molecular, and optical science, the term light dressed state refers to a quantum state of an atomic or molecular system interacting with a laser light in terms of the Floquet picture, i.e. roughly like an atom or a molecule plus a photon. The Floquet picture is based on the Floquet theorem in differential equations with periodic coefficients. Mathematical formulation The Hamiltonian of a system of charged particles interacting with a laser light can be expressed as : H=\sum_i \frac\left mathbf_i-\frac\mathbf\right2 +V(\), \ \ \ \ \ \ \ \ \ \ \ (1) where \mathbf is the vector potential of the electromagnetic field of the laser; \mathbf is periodic in time as \mathbf(t+T)=\mathbf(t). The position and momentum of the i\,-th particle are denoted as \mathbf_i \, and \mathbf_i \,, respectively, while its mass and charge are symbolized as m_i \, and z_i \,, respectively. c \, is the speed of light. By virtue of this time-periodicity of the laser field, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interference (wave Propagation)
In physics, interference is a phenomenon in which two waves combine by adding their displacement together at every single point in space and time, to form a resultant wave of greater, lower, or the same amplitude. Constructive and destructive interference result from the interaction of waves that are correlated or coherent with each other, either because they come from the same source or because they have the same or nearly the same frequency. Interference effects can be observed with all types of waves, for example, light, radio, acoustic, surface water waves, gravity waves, or matter waves. Etymology The word ''interference'' is derived from the Latin words ''inter'' which means "between" and ''fere'' which means "hit or strike", and was coined by Thomas Young in 1801. Mechanisms The principle of superposition of waves states that when two or more propagating waves of the same type are incident on the same point, the resultant amplitude at that point is equal to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rabi Oscillation
In physics, the Rabi cycle (or Rabi flop) is the cyclic behaviour of a two-level quantum system in the presence of an oscillatory driving field. A great variety of physical processes belonging to the areas of quantum computing, condensed matter physics, condensed matter, atomic and molecular physics, and nuclear and particle physics can be conveniently studied in terms of two-level quantum mechanical systems, and exhibit Rabi flopping when coupled to an oscillatory driving field. The effect is important in quantum optics, Nuclear magnetic resonance, magnetic resonance and quantum computing, and is named after Isidor Isaac Rabi. A two-level system is one that has two possible energy levels. These two levels are a ground state with lower energy and an excited state with higher energy. If the energy levels are not degenerate (i.e. not having equal energies), the system can absorb a quantum of energy and transition from the ground state to the "excited" state. When an atom (or some ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density Matrix
In quantum mechanics, a density matrix (or density operator) is a matrix that describes the quantum state of a physical system. It allows for the calculation of the probabilities of the outcomes of any measurement performed upon this system, using the Born rule. It is a generalization of the more usual state vectors or wavefunctions: while those can only represent pure states, density matrices can also represent ''mixed states''. Mixed states arise in quantum mechanics in two different situations: first when the preparation of the system is not fully known, and thus one must deal with a statistical ensemble of possible preparations, and second when one wants to describe a physical system which is entangled with another, without describing their combined state. Density matrices are thus crucial tools in areas of quantum mechanics that deal with mixed states, such as quantum statistical mechanics, open quantum systems, quantum decoherence, and quantum information. Definition and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olga Kocharovskaya
Olga Anatolevna Kocharovskaya (russian: Ольга Анатольевна Кочаровская) is a distinguished professor of physics at Texas A&M University, known for her contributions to laser physics, quantum optics and gamma ray modulation. Education Kocharovskaya earned a doctorate in 1986 from N. I. Lobachevsky State University of Nizhny Novgorod. Her research at that time was the first to study electromagnetically induced transparency. Research and career Kocharovskaya began her postdoctoral research at the Institute of Applied Physics Russian Academy of Sciences in 1986, where she became a senior scientist in 1992 and group leader in 1996. From 1990 to 1996, she was also a visiting research scientist at the Université libre de Bruxelles. She completed a habilitation thesis titled "''Lasers without population inversion''" in 1996, awarded by the Commission of the Russian Federation. In 1998, she joined Texas A&M University as an associate professor, and became ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Dot
Quantum dots (QDs) are semiconductor particles a few nanometres in size, having light, optical and electronics, electronic properties that differ from those of larger particles as a result of quantum mechanics. They are a central topic in nanotechnology. When the quantum dots are illuminated by UV light, an electron in the quantum dot can be excited to a state of higher energy. In the case of a semiconductor, semiconducting quantum dot, this process corresponds to the transition of an electron from the valence band to the conductance band. The excited electron can drop back into the valence band releasing its energy as light. This light emission (photoluminescence) is illustrated in the figure on the right. The color of that light depends on the energy difference between the conductance band and the valence band, or the transition between discrete energy states when band structure is no longer a good definition in QDs. In the language of materials science, nanoscale semiconductor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Wire
In mesoscopic physics, a quantum wire is an electrically conducting wire in which quantum effects influence the transport properties. Usually such effects appear in the dimension of nanometers, so they are also referred to as nanowires. Quantum effects If the diameter of a wire is sufficiently small, electrons will experience quantum confinement in the transverse direction. As a result, their transverse energy will be limited to a series of discrete values. One consequence of this quantization is that the classical formula for calculating the electrical resistance of a wire, : R = \rho \frac, is not valid for quantum wires (where \rho is the material's resistivity, l is the length, and A is the cross-sectional area of the wire). Instead, an exact calculation of the transverse energies of the confined electrons has to be performed to calculate a wire's resistance. Following from the quantization of electron energy, the electrical conductance (the inverse of the resistance) is fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Well
A quantum well is a potential well with only discrete energy values. The classic model used to demonstrate a quantum well is to confine particles, which were initially free to move in three dimensions, to two dimensions, by forcing them to occupy a planar region. The effects of quantum confinement take place when the quantum well thickness becomes comparable to the de Broglie wavelength of the carriers (generally electrons and holes), leading to energy levels called "energy subbands", i.e., the carriers can only have discrete energy values. A wide variety of electronic quantum well devices have been developed based on the theory of quantum well systems. These devices have found applications in lasers, photodetectors, modulators, and switches for example. Compared to conventional devices, quantum well devices are much faster and operate much more economically and are a point of incredible importance to the technological and telecommunication industries. These quantum well devices a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
