Nonlinear absorption and refraction in indium arsenide

Abstract

z -scan experiments and beam propagation modeling were conducted to determine the nonlinear absorption and refractive index cross sections of n-type indium arsenide (InAs). A doubled carbon dioxide pulsed laser operating at 4.78μm was used to generate free carriers via two-photon absorption. Using published values for the two-photon absorption coefficient in InAs, a nonlinear beam propagation model and a data fitting routine were used to extract the nonlinear absorption and refractive index cross sections.

Wavelength dependence of two photon and free carrier absorptions in InP

“…The accuracy of this assumption was verified by measuring the nonlinear transmission using ns lasers at different spot sizes. 1is numerically solved via the operator splitting method [8][9][10]. The right side of the equation is separated into linear and nonlinear operations which are solved independently.…”

Crystal growth and below-bandgap optical absorption studies in InAs for non-linear optic applications

“…InAs also exhibits very strong non-linear optical properties because of its small bandgap [2][3][4]. InAs has a non-linear optical coefficient of 200 Â 10 -12 m/V and a very high two-photon absorption coefficient (b) of 890 cm/GW [5]. To fully exploit the high non-linear optical coefficient of InAs, it should possess high linear transmission (extremely low absorption) for below-bandgap energy photons [6].…”