Generation of continuously tunable terahertz-wave radiation exploited by stimulated polariton scattering

The characteristics of a coherent tunable terahertz-wave source have been experimentally investigated in detail. By using a difference frequency generation as a result of stimulated Raman scattering by polaritons in MgO:LiNbO₃ crystals, the signal wave was continuously tuned in the range of 1.069–1.075 μm, which corresponded to a terahertz-wave in the wide range from 227 to 104 μm (1.3 to 2.9 THz). The highest output signal pulse energy at the pumping level of 44 mJ/pulse was 1.8 mJ/pulse with 20 mW seeder injection, and the terahertz peak power was 139 mW at the wavelength of 143 μm. This source has the advantages of simple alignment, simplicity of tuning, and compactness that makes the device more attractive.