The process of Terahertz(THz) generation by Difference Frequency Generation(DFG) based on Cavity Phase Matching(CPM) in a GaAs crystal is investigated. The relation between the terahertz wavelength and optimum cavity length is obtained. Combined with the influence of temperature on terahertz wavelength, the continuously tunable THz wave in terahertz frequency can be realized. The power conversion efficiency of terahertz generation based on cavity phase matching can reach to 1.33% under the condition that pump wave travels round trip for 20 times in the microcavity. 581.41 μm of the cavity length based on CPM amounts to 23 mm of crystal length based on Quasi-Phase Matching(QPM) at the same efficiency. It can be predicted that the terahertz sources prepared by cavity phase matching will have broad application prospect, and the results can provide certain reference for related experiments.%研究了基于 GaAs 晶体的腔相位匹配(CPM)差频产生太赫兹的过程,得出太赫兹波长与最优腔长之间的关系,并结合温度对太赫兹波长的影响,可实现太赫兹波段范围内的连续调谐输出.当泵浦光在微腔中往返20次时,腔相位匹配产生太赫兹的功率转换效率可达1.33%,在效率相同的情况下,CPM 腔长为581.41 μm 时相当于准相位匹配(QPM)条件下的晶体长度约23 mm.可以预见由腔相位匹配原理制备的太赫兹源将具有广阔的应用前景,该结果对相关实验具有一定的参考价值.
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