Nonlinear Optical Properties of Selectively Contacted Gallium Arsenide Doping Superlattices

The modulation of absorption in GaAs doping superlattices (DSL’s) has been previously demonstrated using optical excitation.1–3 By using selective contacts to the n- and p-type layers, Chang-Hasnain et al.4 demonstrated the tunability of the optical absorption by means of electrical bias. In this paper, we show experimental results whereby the optical modulation of the optical properties is examined as a function of the applied electrical bias. From modulated transmission and reflection data, changes in the real and imaginary parts of the refractive index are determined. Additionally, we have examined the recovery time of the DSL following picosecond laser illumination and show that it is substantially decreased with the use of an external circuit.