D. V. Kosachiov | Searcharxiv

arXiv1999

Efficient microwave-induced optical frequency conversion

Frequency conversion process is studied in a medium of atoms with a $Λ$ configuration of levels, where transition between two lower states is driven by a microwave field. In this system, conversion efficiency can be very high by virtue of the effect of electromagnetically induced transparency (EIT). Depending on intensity of the microwave field, two regimes of EIT are realized: ''dark-state'' EIT for the weak field, and Autler-Townes-type EIT for the strong one. We study both cases via analytical and numerical solution and find optimum conditions for the conversion.

quant-ph↗

arXiv1999

Generation of continuous-wave THz radiation by use of quantum interference

We propose a scheme for generation of continuous-wave THz radiation. The scheme requires a medium where three discrete states in a $Λ$ configuration can be selected, with the THz-frequency transition between the two lower metastable states. We consider the propagation of three-frequency continuous-wave electromagnetic (e.m.) radiation through a $Λ$ medium. Under resonant excitation, the medium absorption can be strongly reduced due to quantum interference of transitions, while the nonlinear susceptibility is enhanced. This leads to very efficient energy transfer between the e.m. waves providing a possibility for THz generation. We demonstrate that the photon conversion efficiency is approaching unity in this technique.

quant-ph↗