The Effects of Intense Terahertz Laser and Magnetic Fields on Optical Properties of a Shallow Impurity in Semiconductors in the Faraday Configuration

The influence of intense terahertz laser and magnetic fields on the total optical absorption coefficient for the transitions between shallow-impurity states 1s and 2p +/- in semiconductors within the Faraday configuration is studied by using the compact density-matrix approach, where the energy levels and wave functions of shallow-impurity states are obtained by using a combination of time-dependent nonperturbative approach and variational method. We find that the transition energy of shallow-impurity states and the dipole matrix element can be not only increased but also decreased by varying the external fields via laser-dressed Coulomb potential. In this way, the saturable absorption and the resonant peak position and magnitude of the total optical absorption coefficient can be effectively tuned with an appropriate choice of the external fields. Moreover, an appreciable effect of cyclotron motion on the total optical absorption coefficient is observed. This gives new degree of freedom in various device applications based on the intradonor transition of electrons.