Resonant generation of terahertz radiation in anisotropic media with permanent dipole moment

The generation of terahertz broadband pulses by optical rectification in nonlinear crystal under condition of laser pulse interaction with quantum particles with permanent dipole moment is examined. If the permanent dipole moment is larger than transition dipole moment, the resonant method is more efficient than nonresonant optical rectification. Estimated conversion efficiency in organics and semiconductor nanostructures can reach 0.1% and higher on order of magnitude.