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where the first contribution, ~, contains the Coulomb-renormalized single-particle energy that is determined by the bandstructure of the solid.The Coulomb renormalization are identical to those that appear in the semiconductor Bloch equations (SBEs), showing that all photon-assisted polarizations are coupled with each other via the unscreened Coulomb-interaction .
The exact reverse of radiative recombination is light absorption. For the same reason as above, light with a photon energy close to the band gap can penetrate much farther before being absorbed in an indirect band gap material than a direct band gap one (at least insofar as the light absorption is due to exciting electrons across the band gap).
Photoluminescence (abbreviated as PL) is light emission from any form of matter after the absorption of photons (electromagnetic radiation). [1] It is one of many forms of luminescence (light emission) and is initiated by photoexcitation (i.e. photons that excite electrons to a higher energy level in an atom), hence the prefix photo- . [ 2 ]
Photoluminescence intensity computed via the Elliott formula. The population of s-like exciton states follow a Boltzmann distribution at 35 Kelvin, where the 1 s population is suppressed to four percent and the dephasing constant is ℏ γ ≈ 1 / , m e V {\displaystyle \hbar \gamma \approx 1/,\mathrm {meV} } .
The nanofocusing technique can create a nanometer-scale "white" light source at the tip apex, which can be used to illuminate a sample at near-field for spectroscopic analysis. The interband optical transitions in individual single-walled carbon nanotubes are imaged and a spatial resolution around 6 nm has been reported. [28]
Most metals reflect almost all visible light, due to the presence of free charges, and are therefore silvery in color or mirror-like. However, some metals like gold and copper are more reddish, and this is due to absorption from intersubband transitions that occur at blue wavelengths.
This technique involves the interference of two-photon interband transitions in solids. It is especially suited for diagnostics on the temporal structure of XUV pulses. The reconstruction of attosecond beating by interference of two-photon transitions is a valuable tool for studying ultrafast processes in materials and can provide insight into ...
Interband cascade lasers (ICLs) are a type of laser diode that can produce coherent radiation over a large part of the mid-infrared region of the electromagnetic spectrum. They are fabricated from epitaxially -grown semiconductor heterostructures composed of layers of indium arsenide (InAs), gallium antimonide (GaSb), aluminum antimonide (AlSb ...