Second harmonic generation by intersub-band transitions in compositionally asymmetrical MQWs

Abstract
We report the first experimental evidence of second harmonic generation due to inter-subband transitions in compositionally asymmetrical multiquantum wells using a continuous CO2 laser. The extremely large value of the second-order susceptibility (χ(2)2ω ~ 7.6×10−7m/V) is ingood agreement with theoretical predictions.