Autocorrelation Measurement of Picosecond Pulses with Two-Photon Absorption

In this work, an autocorrelation measurement method is proposed to obtain the key information of picosecond pulses using the two-photon absorption (TPA) effect. The autocorrelation measurement process is simulated with a linear tuning of the pulse repetition frequency (PRF). Given the dispersion of picosecond pulses, the profile of the autocorrelation signal is broadened symmetrically. Moreover, the dispersive distribution in time-frequency domain of picosecond pulses and the different bandwidth of the TPA spectrum of materials should bring in sub pulses in the autocorrelation signal with the relative different delay. As shown in simulations, with an ideal broadband two-photon response spectrum, only the broadening of autocorrelation trace appears. But the detection with a narrowband two-photon response spectrum displays the greater sensitivity for pulse dispersion of the edge of the pulse, benefiting from the more sub pulses. Detections of picosecond pulses within the space wireless communication band region generally employ the photoconductive antenna and electro-optic effect in free space. However, with respect to the TPA effect in the specific materials, we could build an extremely compact autocorrelation measurement configuration for the key information extraction of picosecond pulses in space wireless communication and astronomical measurement, which would provide the same information as conventional detections about the autocorrelation signal of picosecond pulses.