增益饱和对光学差频产生太赫兹辐射的功率和稳定性的影响

数值模拟并分析了以GaSe晶体为例对光学差频产生太赫兹（THz）波的特性.结果表明：当THz波长为227.5 μm，晶体长度为26.3 mm时，产生THz波功率达到增益饱和，在增益饱和点输出最高峰值功率可以达到945 W.由于晶体吸收的影响，THz波的增益饱和区是输出功率的非稳定区，而THz波的输出稳定区位于增益饱和区之后，在稳定区的THz波稳定性取决于抽运光的稳定性.当THz波波长为227.5 μm时，达到稳定区所需晶体长度为37.9 mm，此时THz波输出峰值功率可以达到735 W. 关键词： 光学差频 太赫兹辐射 稳定性

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

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 227.5μm and at the corresponding crystal length of 37.9 mm in stable region.