A method and system for measuring beam waist radius based on z-scanning

Abstract

The invention discloses a beam waist radius measurement method and system based on Z-scanning. Using the Z-scanning system, the sample is firstly controlled to move along the z-axis of the measuring beam, and the energy and energy of the reference beam when the sample is in different z-axis positions are respectively obtained. Measure the energy of the light beam transmitted through the sample, which are the first energy and the second energy respectively, and obtain the transmittance of the sample at each z-axis position, and then according to the position data of each z-axis position and the transmittance of the sample at each z-axis position The position at the beam waist of the measuring beam is obtained through the ratio, and the beam waist radius of the measuring beam is obtained by fitting according to the transmittance at each z-axis position. The invention uses the Z scanning system itself to measure the beam waist radius, and can improve the measurement accuracy of the beam waist radius compared with the prior art.

Description

Technical field [0001] The present invention relates to the field of nonlinear optical and optical detection techniques, and more particularly to a radius measurement method and system based on a Z scan. Background technique [0002] The three-order optics of the substance, including non-linear refraction (proportional to non-linear solid), nonlinear absorption (proportional to nonlinear imaginary) and other nature including nonlinear scattering, etc., is a non-linear light limit And even the foundation of laser protection. [0003] Since the opening Z scanning technology has the advantage of low cost, relatively simple construction, technical maturation, since SHEIK-Bahae et al. Since 1989, it has been measured as a standard three-order and even high-order nonlinear absorption factor. In recent years, Z scanning technology is extremely widely used in photochemistry, atomic and molecular physics, nonlinear optical applications, and derived a variety of Z scanning systems. [0004...

AI Technical Summary

Problems solved by technology

In the prior art, the direct calculation method or the knife-edge method is used to measure the beam waist radius. However, the beam waist radius obtained by the direct calculation method is restricted by the incident beam radius and the measurement accuracy of the focus position. In addition, nonlinear effects may occur under strong light , resulting in changes in the beam radius, which may also affect the measurement of the beam waist radius. However, the measurement process of the knife-edge method is cumbersome and time-consuming, and the knife-edge scanning curve does not conform to the model due to irregular knife-edge edges and diffraction and scattering. The problem that the measurement accuracy of the beam waist radius decreases

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