Optical absorption in degenerate semiconductors

Optical absorption in a degenerate Bose gas

We here develop a theory on optical absorption in a dilute Bose gas at low temperatures. This theory is motivated by the Bogoliubov theory of elementary excitations for this system, and takes into account explicitly the modification of the nature and dispersion of elementary excitations due to Bose-Einstein condensation. Our results show important differences from existing theories. PACS number...

Electron Distribution in Degenerate Semiconductors

As we’ve discussed, to get the right density of states we should replace m by me . In addition, the energy that appears in the square root in the density of states really came from changing variables from momentum to energy. At the bottom of the conduction band, the electrons presumably have very little momentum. That is, the first state to be filled corresponds to an electron wave which is a s...

Two photon absorption, nonlinear refraction, and optical limiting in semiconductors

Quantum of optical absorption in two-dimensional semiconductors.

The optical absorption properties of free-standing InAs nanomembranes of thicknesses ranging from 3 nm to 19 nm are investigated by Fourier transform infrared spectroscopy. Stepwise absorption at room temperature is observed, arising from the interband transitions between the subbands of 2D InAs nanomembranes. Interestingly, the absorptance associated with each step is measured to be ∼1.6%, ind...

Sensitive mid-infrared detection in wide-bandgap semiconductors using extreme non-degenerate two-photon absorption

Identifying strong and fast nonlinearities for today’s photonic applications is an ongoing effort1. Materials2–5 and devices6–9 are typically sought to achieve increasing nonlinear interactions. We report large enhancement of two-photon absorption through intrinsic resonances using extremely non-degenerate photon pairs. We experimentally demonstrate two-photon absorption enhancements by factors...