Effects of gain saturation in terahertz radiation based on difference frequency generation

Abstract

Numerical studies of terahertz （THz） radiation based on difference frequency generation in GaSe crystal are reported. When the gain saturation is achieved at a wavelength of 227.5 μm，which corresponds to a crystal length of 26.3 mm，the peak output power for THz radiation reaches 945 W. As a result of crystal absorption，the gain saturation region of THz radiation is the unstable output region，which is in front of the stable output region; and the stability of THz radiation is determined by the stability of pump. The peak output power for THz radiation reaches 735 W at the wavelength of 227.5 μm and at the corresponding crystal length of 37.9 mm in stable region.