ИСТИНА

The study of non-classical states in the terahertz range is hampered by high terahertz absorption in the nonlinear crystals and by a considerable noise at room temperatures due to the thermal radiation. The possibility for observing the non-classicality in the case of optical-terahertz biphotons depends on the ratio between numbers of SPDC-generated terahertz photons and background thermal ones. The correlation function and the noise reduction factor have been calculated for the SPDC-generated optical-terahertz biphoton fields. The prospects of experimental investigation of these states are discussed.