Generation of Terahertz Radiation in InP:Fe Crystals Due to Second-Order Lattice Nonlinearity

The generation of the second-harmonic radiation of a gyrotron with an operating frequency of 263 GHz due to second-order lattice nonlinearity in iron-doped indium-phosphide crystals is experimentally demonstrated. It is shown that second-harmonic radiation can be used in the magnetospectroscopy of semiconductor nanostructures. The possibility of generating the difference frequency in these crystals excited by two mid-IR sources with close wavelengths is discussed.