QUANTUM-WELL-NUMBER DEPENDENCE OF OPTICAL 2ND-HARMONIC GENERATION IN MULTIPLE-STEP QUANTUM-WELLS

On the basis of a microscopic local-field formalism, optical second-ha rmonic (SH) generation arising from intersubband transitions in a mult iple-step quantum-well (MSQW) structure is investigated theoretically. In an internal reflection configuration the SH energy reflection coef ficient as a function of the frequency and the number of quantum wells is calculated for a near-double-resonant GaAs/AlGaAs MSQW structure. The numerical results show that the quantum-well-number dependence of the SH conversion efficiency exhibits a pronouncedly oscillatory behav ior. This phenomenon is ascribed to the electromagnetic coupling among quantum wells in the MSQW structure.