周期结构GaAs晶体ps脉冲差频产生窄带THz辐射的研究

The study of narrow-band terahertz-wave generation by difference frequency mixing in periodical-inverted GaAs crystal with ps pump pulses

计算模拟了在ps脉冲抽运周期结构GaAs晶体差频产生窄带THz波过程中,对于不同波长、不同脉宽的抽运光,周期结构GaAs晶体的走离长度和最佳周期长度的变化,并对计算结果进行了理论分析.研究了周期结构GaAs晶体的畴数对THz波光谱的影响.根据GaAs晶体温度色散公式,计算并分析了晶体最佳周期长度的温度调谐特性,研究了温度变化对THz波光谱的影响,提出了通过温度调谐实现在周期结构GaAs晶体中产生宽调谐、窄带宽THz波的新方法,该计算结果为下一步的实验研究提供了理论基础.

In this paper,the tuning of walk-off length and the optimal period of periodical-inverted GaAs crystal in narrow-band terahertz-wave generation by difference frequency mixing was numerical simulated and analyzed in the condition of different wavelengths and durations of pump pulse. The influence of the number of domains of periodically-inverted GaAs crystal on the THz-wave spectrum was also studied. The temperature tuning properties in periodical-inverted GaAs crystal were calculated and analyzed with the temperature dependent Sellmeier function of GaAs crystal; the influence of temperature tuning on the THz-wave spectrum was also studied. The simulation showed a new way to generate the wide-tunable narrow-band THz wave with temperature tuning. These theoretical calculations served for the subsequent experiment as theoretical basis and reference.