频谱可调制的太赫兹波具有广泛的应用价值.利用一台纯相位式的液晶空间光调制器对飞秒激光脉冲进行空间整形,通过改变飞秒激光脉冲的横向空间分布,实现太赫兹波频谱的调制.在实验中,利用光泵浦整流方式产生太赫兹波,并利用太赫兹时域光谱系统对太赫兹信号进行探测.通过GS算法在液晶空间光调制器上加载不同的相位图,获得了不同的飞秒激光脉冲横向空间分布.通过改变探测距离和飞秒脉冲的空间分布参数,实现了太赫兹波频谱的调制.还利用菲涅尔衍射算法对这一过程进行了理论模拟,理论模拟结果与实验结果吻合的较好,这充分说明了基于飞秒脉冲空间整形的太赫兹光谱调制技术的可行性.

Terahertz wave with modulation spectrum is valuable in many fields.Terahertz spectrum has been modulated with a pure-phase liquid crystal spatial light modulator by shaping the femtosecond laser beam profile.In the experiment,terahertz wave is generated by femtosecond laser pulses in mode of Optical Rectification and then its signals are detected by a terahertz time-domain spectroscopy system.Phase maps obtained with the GS algorithm are loaded to get the shaped beam profile.Therefore,Terahertz spectrum has been successfully modulated by changing the detection range and beam profile parameters.Simultaneously,the simulations have been performed with the Fresnel diffraction,and they agree with the experimental results well.The results show that the modulation of the THz spectrum with this method is feasible.