Nonlinear-optical absorption in InGaAs/InAlAs multiple quantum wells

Abstract

We have measured the room-temperature intensity dependence of the optical transmission of an In(0.53)Ga(0.47)As/In(0.52)Al(0.48)As multiple-quantum-well structure from 1.5 to 1.7 microm. The absorption is calculated from the transmission by taking into account the wavelength dependence of the reflection coefficients. An intensityof 15 kW cm(-2) is required to reduce the absorption by one half for excitation at the edge of the 1H-lC transition absorption band. For intensities exceeding 10(7) W cm(-2), complete saturation of the absorption is observed. A theoretical model is described that fits the intensity dependence of the absorption right upto saturation at two wavelengths and predicts a carrier lifetime of 0.75 nsec, which has been confirmed by independent measurements.

Observation of optical bleaching at 1.06μm in AlInAs/AlGaInAs multiple quantum wells

“…A more direct comparison to our samples is the AlInAs/GaInAs MQW system, but a broad range of results have been obtained here as well. MBE MQWs in this system have demonstrated bleaching lifetimes ranging from 20 to 0.75 ns [7,22]. The direct comparison to our results is the MOVPE-grown AlGaInAs/AlInAs SESA structure analyzed by Huang et al, who report a bleaching relaxation time on the order of 100 ns [10].…”

A unified view of one-electron mechanisms for non-linear refraction in a semiconductor

“…On the other hand, one can also consider the case y p rl (but still with y @ rz a possible situation in semiconductors) for which (7) may be rewritten as…”

“…In principle, of course, a complete theory of nonlinear optical processes in semiconductors requires a many-electron treatment [3]. Nonetheless, one-electron theories have a role to play, as can be seen from the impressive agreement with experiment not only for bandgap resonant non-linear refraction in InSb [1,4] and InAs [S], but also for four-wave mixing via free carriers at low frequencies in InSb [S] and for intensity-dependent absorption in GaInAs/AlInAs multiple quantum wells [7].…”