Abstract

Far infrared optical properties of the semiconductor quantum wells (QVVs) have attracted the attention of many authors. Large oscillator strengths for the intersubband transitions (IST) that have been observed^1.2 make the 1ST attractive for many applications. While the second-order nonlinearities³,*¹ have been, studied rather extensively, the third- order ones are only beginning to incite curiosity. Third-harmonic generation has been lately reported in Ref. 5, and three photon resonant emission in Ref. 6. Until now, most of the researchers concentrated on tire iron- linearities at frequencies close to the frequency of the IST, i.e., χ⁽³⁾(ω,ω,-ω,ω), thus taking advantage of the triple resonance in the expression for the χ⁽³⁾.

© 1993 Optical Society of America