半绝缘GaAs倍频效应的研究

Research on the double-frequency effect of semi-insulating GaAs

理论研究了GaAs的倍频效应,当基频光电场的偏振方向沿[111]方向时,倍频效应最显著;当基频光垂直于半球形GaAs样品的(001)底面入射时,产生的二次谐波沿(001)面传播。首次从光电流随基频光偏振方向的变化这一角度验证了波长为1.3μm的基频光沿GaAs晶体的[001]方向入射时的倍频吸收各向异性理论;实验测得了样品的光电流随外加偏压的非线性变化关系,实验中没有观察到光电流随外加偏压的增加而饱和的现象,进一步证明了GaAs样品中产生了倍频吸收。

The double-frequency effect in GaAs single crystal is studied theoretically,and it is found to be the most significant when the fundamental optical field is along [111] direction;the second-harmonic will radiate parallel to the(001) plane when the incident light is propagating perpendicularly to the(001) bottom of the GaAs sample.The double-frequency absorption(DFA) in the semi-insulating GaAs sample is confirmed by the dependence of the photocurrent on the azimuth in agreement with the anisotropy of DFA in GaAs single crystal,the photocurrent nonlinearly dependent on the bias and no saturation with the bias.