Dispersion-induced nonlinearities in semiconductors

Dispersion-induced non-linearities in semiconductors

Dispersion of nondegenerate nonlinear refraction in semiconductors.

We use our recently developed beam-deflection technique to measure the dispersion of the nondegenerate nonlinear refraction (NLR) of direct-gap semiconductors. The magnitude and sign of the NLR coefficient n2(ωa; ωb) are determined over a broad spectral range for different values of nondegeneracy. In the extremely nondegenerate case, n2(ωa; ωb) is positively enhanced near ...

Optical Nonlinearities in the Transparency Region of Bulk Semiconductors

I . INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258 11 . BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259 1 . Nonlinear Absorption and Refracrion . . . . . . . . . . . . . . . . . . 259 2 . Nonlinear Polarization and the Definitions of Nonlinear Coeflcients . . . . . 261 111 . THEORY OF FWUND-ELECTRONIC NONLINEARITIES: TWO-BAND MODEL . . . . . 27...

Extreme THz nonlinearities in bulk and nanostructured semiconductors

Phase-locked electromagnetic transients in the terahertz (THz) spectral domain have become a unique contact-free probe of the femtosecond dynamics of low-energy excitations in semiconductors. Access to their nonlinear response, however, has been limited by a shortage of sufficiently intense THz emitters. Here we introduce a novel high-field source for THz transients featuring peak amplitudes of...

Nondegenerate Two- and Three-Photon Nonlinearities in Semiconductors

Two-photon absorption, 2PA, in semiconductors is enhanced by two orders of magnitude due to intermediate-state resonance enhancement, ISRE, for very nondegenerate (ND) photon energies. Associated with this enhancement in loss is enhancement of the nonlinear refractive index, n2. Even larger enhancement of three-photon absorption is calculated and observed. These large nonlinearities have implic...