Sub-THz-Repetition Optical Waveform Measurement by Novel THz-wave Autocorrelator

For observation a high-repetition optical waveform, we had proposed a THz wave autocorrelator consisting of an optical delay line and high-speed photodiodes, and demonstrated observation of a 100-GHz sinusoidal wave. In this paper, based on an assumpton that a higher THz-wave interference enables us to observe a higher-repetition waveform, we improved the autocorrelator for enhancing the interference between THz waves. Experimental results showed an autocorrelation of sinusoidal waveforms of up to 950 GHz, which testifies the feasibility of the proposed method.