01623nas a2200205   4500008004100000020001400041245011600055210006900171260000800240300001200248490000600260520099500266100002001261700001801281700001801299700002001317700001501337700001601352856004901368       1994                        eng d  a0268-124200aSUBCUBIC POWER DEPENDENCE OF 3RD-HARMONIC GENERATION FOR INPLANE, FAR-INFRARED EXCITATION OF INAS QUANTUM-WELLS0 aSUBCUBIC POWER DEPENDENCE OF 3RDHARMONIC GENERATION FOR INPLANE   cMay  a634-6370 v93 a<p>Large third-order, free-carrier nonlinear susceptibilities, chi(3) (to approximately 0.2 esu), and subcubic dependence of the third-harmonic power on the incident intensity, have been observed between 19 cm-1 and 23 cm-1 for InAs/AlSb quantum wells with electron sheet densities between 2.5 x 10(12) cm-2 and 8 X 10(12) cm-2. We find that the transmission of the fundamental, and the samples' DC conductivity, decrease with increasing incident intensity, indicating a large rise in the scattering rate. Using the intensity-dependent transmission to account for absorption in the sample is not sufficient to recover a cubic power law for the third-harmonic intensity. In addition, given the increased scattering rate indicated by the conductivity data, the bulk free-carrier chi(3) due to non-parabolicity should decrease dramatically with increasing fundamental intensity, contrary to our results. Thus, non-parabolicity alone cannot account for the observed third-harmonic response.</p>1 aMarkelz, A., G.1 aAsmar, N., G.1 aGwinn, E., G.1 aSherwin, M., S.1 aNguyen, C.1 aKroemer, H.  uhttps://markelz.physics.buffalo.edu/node/267