Simple femtosecond pulse width measuring system

Abstract

The invention discloses a simple femtosecond pulse width measuring system. The system comprises a focusing element, a femtosecond pulse time-delay splitting subsystem, a high-pressure generating module and a data collecting and processing system; when the femtosecond optical ultrashort pulse with unknown pulse width passes through the focusing element and enters the femtosecond pulse time-delay splitting subsystem, the femtosecond optical ultrashort pulse is divided into two beams by a beam splitter mirror in the subsystem, the optical path difference of two lights is controlled by adjusting output signals of the high-pressure generating module to change the expansion amount of piezoelectric ceramics. Finally, said two lights arrive at the same position of a two-photon detector through a reflector. The sequential variation of signals measured by the two-photon detector is obtained by changing the high-pressure signals for controlling the piezoelectric ceramics namely changing the delay time of the pulse, and the width of the femtosecond optical ultrashort pulse is obtained through data treatment. The focusing element, the piezoelectric ceramics and the two-photon detector are employed in the simple femtosecond pulse width measuring system, thus the measuring system is simple and compact in structure and strong in feasibility.

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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