Coherent population trapping in intersubband photocurrent spectra
M. Z. Maialle, Marcos H. Degani
We present results from numerical simulations of the photocurrent generated by intersubband optical transitions in a double quantum well coupled with a continuum of extended states. The photocurrent spectra are obtained directly from the time-dependent Schr\"odinger equation for the coherent regime without any adjusting parameters in the calculations other than the ones that define the physical system, also in a nonperturbative way and without basis-set expansions or truncations. A realistic representation of a three-level system in the Lambda (``$\ensuremath{\Lambda}$'') configuration is investigated when two bound states in each quantum well are coupled by exciting fields via an excited quasibound state. Resonance between the exciting fields and the quantum states leads to coherent effects such as Rabi-dressed states, electromagnetically induced transparency, and population trapping, which are investigated in terms of the photocurrent spectral changes; that is, the coherent optical dynamics can be seen from the photocurrent signal. An excitation scheme involving two-photon absorption was proposed to produce the population-trapping effects using only one exciting field.
Physical Review B•Apr 11, 2011•5 citations