A Simple Femtosecond Pulse Width Measurement System

Abstract

The invention discloses a simple femtosecond pulse width measurement system, which includes a focusing element, a femtosecond pulse splitting delay subsystem, a high voltage generation module and a data acquisition and processing system; when a femtosecond optical ultrashort pulse with unknown pulse width , after passing through the focusing element, it enters the femtosecond pulse splitting and delay subsystem. In this subsystem, the femtosecond optical ultrashort pulse is divided into two beams by the beam splitter. The optical path difference between the two beams is adjusted by the output of the high-voltage generating module. The signal is thus controlled by changing the expansion and contraction of the piezoelectric ceramic. The last two beams of light arrive at the same position on the two-photon detector through the reflector. By changing the high-voltage signal controlling the piezoelectric ceramic, that is, changing the delay time of the pulse, the timing change of the signal measured by the two-photon detector is obtained, and the width of the femtosecond optical ultrashort pulse is obtained through data processing. The invention adopts light-gathering elements, piezoelectric ceramics and two-photon detectors, and has the characteristics of simplicity, strong feasibility and compact structure.

Description

technical field [0001] The invention relates to the field of optical measurement technology, in particular to a simple measurement system for femtosecond pulse width, which is used to measure the pulse width of an ultrashort optical pulse whose optical pulse width reaches the femtosecond level. Background technique [0002] The current common methods for measuring laser pulses are self-referencing spectral phase coherent electric field reconstruction method, frequency-resolved optical switching method and autocorrelation method. The general idea is: divide the laser into two beams, add a mechanical stepping motor in the optical path of one of the beams, then converge the two beams on the nonlinear crystal, control the stepping motor and use phase matching to realize the laser pulse width Measurement. However, the aforementioned pulse width measurement methods all need to use nonlinear crystals and perform phase matching to realize this process, which is relatively complicat...

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Problems solved by technology

However, the aforementioned pulse width measurement methods all need to use nonlinear crystals and perform phase matching to realize this process, which is relatively complicated and difficult to operate.

In addition, in recent years, there is no need to use nonlinear crystals, and the method of using photodetectors with nonlinear responses to measure the width of optical pulses is basically the same as the previous method, and nonlinear crystals are omitted, but this pulse width measurement method requires High-precision mechanical stepping motor to complete, high requirements for hardware equipment

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