||D. A. B. Miller, D. S. Chemla, D. J.
Eilenberger, P. W. Smith, A. C. Gossard, and W. T. Tsang, "Large Room-Temperature
Optical Nonlinearity in GaAs/Ga1-xAlxAs Multiple Quantum Well
Structures," Appl. Phys. Lett. 41, 679-681, (1982).
Reports the first
measurements of optical absorption saturation in GaAs/GaAlAs multiple quantum well (MQW)
structures at room temperature near the heavy hole exciton peak. Linear absorption shows
distinct exciton peaks at room temperature in the MQW and the authors deduce this is
because the confinement increases exciton binding energy without increasing LO phonon
coupling. This room-temperature MQW absorption also saturates more readily than that in a
comparable GaAs sample; the measured saturation intensity is 580 W/cm/sup 2/ with a
recombination time of 21 ns in a MQW with 102-AA GaAs layers. From this the authors
predict a nonlinear refraction coefficient n/sub 2/ approximately 2*10/sup -5/ cm/sup
2//W. This large nonlinearity should permit room-temperature optical devices compatible
with laser diode wavelengths, materials and power levels
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