Coherent control of intersubband optical gain and phonon emission in semiconductor heterostructures

We present results for two coherent control schemes in semiconductor heterostructures obtained within Boltzmann-Bloch equations. The latter are obtained from Dyson's equation within the Keldysh nonequilibrium Green's function approach and allow a microscopic analysis of coherent control schemes in semiconductors. Here we focus on the coherent control of optical gain and longitudinal optical phonon emission rates in intersubband transitions in a three-subband model of a biased asymmetric double well. We show that by coupling the two energetically close subbands with a coherent microwave field, we can induce coherence into the carriers in the double well, thus manipulating intersubband transitions. By adjusting the phase of the microwave field, we can achieve significant modification to the gain spectra for light pulses shorter than the period of the low frequency intersubband polarization. Similarly, LO-phonon induced intersubband transitions can be controlled due to quantum interference between electron-lattice and electron-light interactions.