Chapter 2 - Terahertz Sources Based on Difference-Frequency Generation for Spectroscopy and Biomaterial Analysis

Abstract

Terahertz (THz) region of the electromagnetic spectrum with the corresponding frequencies between 0.1THz and 10THz is very attractive. The generation and detection of THz radiation is difficult; scaling and extrapolating known concepts of the microwave or infrared ranges is not possible. Recent advances however make THz radiation attractive for a much wider range of activities. With increased number of many research teams and their constant efforts, recently this gap between photonics and electronics is filled and has a potential to fulfill real-world applications. We have focused on the development of dual-wavelength solid-state lasers operated at 1μm. The realization of a compact, cost-efficient, and frequency-tunable THz sources was presented in this chapter. The principle of THz wave generation is based on the difference-frequency generation in nonlinear optical (NLO) crystals on the basis of NLO method. A high-resolution THz spectroscopic system with an automatic frequency scanning control was constructed. The THz spectroscopy system has potential applications in biomedical engineering, pharmaceutical industry, and nondestructive analysis of materials.