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The Stark effect is the shifting and splitting of spectral lines of atoms and molecules due to the presence of an external electric field. It is the electric-field analogue of the Zeeman effect , where a spectral line is split into several components due to the presence of the magnetic field .
As can be shown by solving the optical Bloch equations for a two-level system due to the optical Stark effect the resonance frequency should shift to higher values, if the pump frequency is smaller than the resonance frequency and vice versa. [6] This is also the typical result of experiments performed on excitons in semiconductors.
In spectroscopy, the Autler–Townes effect (also known as AC Stark effect), is a dynamical Stark effect corresponding to the case when an oscillating electric field (e.g., that of a laser) is tuned in resonance (or close) to the transition frequency of a given spectral line, and resulting in a change of the shape of the absorption/emission spectra of that spectral line.
A phonon is a collective excitation in a periodic, elastic arrangement of atoms or molecules in condensed matter, specifically in solids and some liquids. A type of quasiparticle in physics , [ 1 ] a phonon is an excited state in the quantum mechanical quantization of the modes of vibrations for elastic structures of interacting particles.
Stark spectroscopy (sometimes known as electroabsorption/emission spectroscopy) is a form of spectroscopy based on the Stark effect.In brief, this technique makes use of the Stark effect (or electrochromism) either to reveal information about the physiochemical or physical properties of a sample using a well-characterized electric field or to reveal information about an electric field using a ...
In physics, the observer effect is the disturbance of an observed system by the act of observation. [1] [2] This is often the result of utilising instruments that, by necessity, alter the state of what they measure in some manner. A common example is checking the pressure in an automobile tire, which causes some of the air to escape, thereby ...
In condensed matter physics, a Kohn anomaly (also called the Kohn effect [1]) is an anomaly in the dispersion relation of a phonon branch in a metal. For a specific wavevector, the frequency (and thus the energy) of the associated phonon is considerably lowered, and there is a discontinuity in its derivative. In extreme cases (that can happen ...
A phonon polariton is a type of quasiparticle that can form in some crystals due to the coupling of photons and lattice vibrations. They have properties of both light and sound waves, and can travel at very slow speeds in the material.