Transient grating effect based femtosecond laser pulse measuring device

Abstract

The invention discloses a transient grating effect based femtosecond laser pulse measuring device. The transient grating effect based femtosecond laser pulse measuring device is characterized in that incident to-be-measured laser pulses are divided into four beams, the three beams generate self-reference light through a transient grating effect of three-phase nonlinear mediums, the three beams and the fourth beam of to-be-measured light are superposed in space and focused into a spectrometer to enable self-reference interference spectrums to be obtained, femtosecond laser pulse shapes, laser spectrums and spectrum phases are calculated through a self-reference spectrum coherent method due to measurement of interference spectrums. The transient grating effect based femtosecond laser pulse measuring device has the advantages of being compact and stable in structure and miniaturized in integrity due to the fact that a focusing system is formed by a concave mirror and a convex mirror or a plane mirror and the concave mirror and not needing an optical polarization element and being applied to femtosecond laser optical systems with the spectrum and the pulse width to be respectively from 200 to 3000nm and 10 to 300fs.

Description

technical field [0001] The invention relates to femtosecond laser pulse measurement, in particular to a femtosecond laser pulse measurement device based on transient grating effect. Background technique [0002] Femtosecond laser has been developed extremely rapidly due to its needs in scientific research, biology, medical treatment, processing, communication, national defense and other fields. As the important optical parameters of femtosecond laser pulses, the shape and pulse width of femtosecond laser pulses are very necessary for their measurement or real-time monitoring. Therefore, finding a simple, convenient, fast and effective method and device for measurement and real-time monitoring plays a very important role in promoting the development of femtosecond laser itself and expanding its application in various fields. [0003] Currently, the most widely used femtosecond laser pulse measurement techniques are: 1. Frequency Resolved Optical Gating (FROG); 2. Spectral Ph...

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Problems solved by technology

However, this method requires optical polarizing elements

Since the optical polarization element is only effective for a specific laser wavelength and has a certain spectral width, this limits the application of this method and instrument to a specific spectral range.

The dispersion of polarized optical components also limits the measurement of short pulses below 10fs

On a similar SRSI method, we have recently proposed two methods based on the self-diffraction effect [see literature 1: J.Liu, Y.L.Jiang, T.Kobayashi, R.X.Li, and Z.Z.Xu, “Self-referenced spectral interferometry based on self-diffraction effect, "J.Opt.Soc.Am.B29(1):29-34(2012); see patent: application number: 201210267065.3] and transient grating effect [see Document 2: J.Liu, F.J.Li , Y.L.Jiang, C.Li, Y.X.Leng, T.Kobayashi, R.X.Li, and Z.Z.Xu, “Transient-grating self-referenced spectral interferometry for infrared femtosecond pulse characterization,” Opt. Lett.37, 4829 (2012); see Patent: Application No.: 201210079324.X] femtosecond laser pulse measurement method, the two methods are not limited by dispersion, but the two methods are still relatively complicated in structure

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