Optical Heterodyne Detection in the Terahertz Region for Accurate Frequency Measurement

We propose an optical heterodyne detection in the terahertz region using parametric up-conversion in a nonlinear LiNbO₃ crystal for accurate frequency measurement. Nonlinear wavelength up-conversion techniques based on frequency stabilized infrared pumping beam allow the spectra in the terahertz region to be determine their frequency and intensity. These are very promising for extending applied research into the terahertz region, and we expect that these will open up new research fields such as wireless information communications in the terahertz region.