Im{<i>?</i>⁽³⁾} spectra of 110-cut GaAs, GaP, and Si near the two-photon absorption band edge

Non-degenerate Two Photon Absorption Spectra of Si Nanocrystallites

The two-photon absorption (TPA) spectrum is an important optical property of semiconductors. It brings valuable information complementary to the one-photon absorption spectrum, gives the limits to the optical transparency of materials, and causes laserinduced damages. Recently, the TPA spectrum of direct-gap nanocrystallites was calculated by Cotter et al. [1] by using the effective-mass approx...

Energy band-gap dependence of two-photon absorption.

We present measurements of the two-photon absorption coefficients beta(2) of 10 different semiconductors having band-gap energies between 1.4 and 3.7 eV. We find that beta(2) varies as E(g)(-3), as predicted by theory. In addition, the absolute values of beta(2) agree with theory, which includes the effect of nonparabolic bands, the average difference being less than 26%. This agreement permits...

Two-photon absorption spectra of carotenoids compounds

Fast, spatially-resolved thermometry of Si and GaP crystals using pump-probe two-photon absorption

Noncontact thermometry with micron-scale lateral spatial resolution and fast time resolution is shown to be enabled by measuring the temperature dependence of two-photon absorption TPA on crystalline semiconductors. In the proof-of-concept experiments reported here, for studies of Si, an Er:fiber laser at =1.56 m is split into pump and probe beams; where they overlap, the large TPA signal chang...

Absorption near band edges in heavily doped GaAs.

The optical-absorption coefficient o.(m) in heavily doped nand p-type GaAs is evaluated for comparison with the observed values of Casey et al. The purpose is to test the theory of electrons in heavily disordered systems derived by Sa-yakanit and the absorption matrix element (ME) which follows from this theory. The present calculation of a(m) begins with the density of electron states (DOS) an...