Intersubband transitions (also known as intraband transitions) are
dipolar allowed optical
excitation
Excitation, excite, exciting, or excitement may refer to:
* Excitation (magnetic), provided with an electrical generator or alternator
* Excite Ballpark, located in San Jose, California
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* Electron exc ...
s between the
quantized electronic
energy levels within the
conduction band
In solid-state physics, the valence band and conduction band are the bands closest to the Fermi level, and thus determine the electrical conductivity of the solid. In nonmetals, the valence band is the highest range of electron energies in w ...
of
semiconductor heterostructures. Intersubband transitions when coupled with an
optical resonator form new, mixed-state
photons
A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they alway ...
. This mixing is referred to as an intersubband cavity-polariton. These transitions exhibit an
anticrossing in energy with a separation known as
vacuum-Rabi splitting, similar to
level repulsion in
atomic physics
Atomic physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. Atomic physics typically refers to the study of atomic structure and the interaction between atoms. It is primarily concerned wit ...
.
Quantum cascade laser
A cascading of intersubband transitions is the mechanism behind a quantum cascade laser which produces a monochromatic coherent light-source at
infrared wavelengths.
Color of metals
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.
See also
*
Fluorescence (interband transitions)
References
*
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Quantum mechanics
Quantum electronics
Quasiparticles
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