Intersubband Optical Absorption in GaAs/AlGaAs Double Quantum Well Structure
Abstract:
The microscopic equations of motion including many-body effects were derived to study the intersubband polarization in the double quantum well structure induced by an ultrafast pumping infrared light. Based on the self-consistent field theory, the transient probe absorption coefficient was calculated. These calculations were beyond the previous steady-state assumption, Transient probe absorption spectra were calculated under different pumping intensity and various pump probe delay.
Fig.1 Calculated effective potential for double quantum well structure (solid thick arrow represents pumping pulse coupled to two subbands, E1 and E3. The dashed thick arrow stands for probe light)
α(ω)=2ωε0√εbLcΙm(Ρ(ω)E(ω))
计算结果中, 吸收系数受泵浦强度影响很大, 如图2所示。
图2 不同泵浦强度下探测光的吸收性质 (负的吸收系数表示探测光的光增益)
Fig.2 Absorption coefficients with various pumping intensities (negative absorption represents optical gain of probe field)