Lagrange Gaussian beam Gouy phase parameter measuring method

Abstract

The invention relates to a Lagrange Gaussian beam Gouy phase parameter measuring method. In the prior art, an optical path structure is complicated, restriction from optical beam coherence is obtained and the measurement in an optical system with high sensitivity and high numerical aperture cannot be realized. According to the invention, the method comprises the following steps of: carrying out sector light shielding modulation on beam wave front by using wave front amplitude modulation technology of the Lagrange Gaussian beam; and selecting beam radial parameters as zero, wherein a circular ring shaped light spot with a gap is formed after beams are gathered; detecting the circular ring shaped light spot with the gap by using a near field optical technology, wherein azimuth angle parameter corresponding to the center of the gap is fundamental mode beam Gouy phase; and obtaining the Gouy phase of any Lagrange Gaussian beam in different spreading positions through simple calculation. The Lagrange Gaussian beam Gouy phase parameter measuring method provided by the invention has the characteristics of simplicity for realization, low requirement on structure positioning, high reliability, strong anti-interference performance, capability of realizing direct measurement with high sensitivity, capability of measuring the Gouy phase in the optical system with high numerical aperture, wide application range and the like.

Description

technical field [0001] The invention belongs to the field of optical technology, and relates to a method for measuring an optical parameter, in particular to a method for measuring a Gouy phase parameter of a Lagrangian Gaussian beam. It is mainly used for the design and optimization of structural properties in the fields of optical resonant cavity, cavity-enhanced spectral analysis, pulse light shaping, photochemistry, and optical instruments. Background technique [0002] The English full name of the Gouy phase is Gouy Phase. The Gouy phase was first discovered by the Frenchman Gouy in 1890. It refers to the additional phase generated by the convergent light wave near the focus compared with the standard spherical wave. This abnormal additional phase actually exists near the focal point of various converging waves. For light waves, the optical Gouy phase is very important. It determines the resonance frequency of various transverse modes of the laser resonator, affects th...

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Problems solved by technology

In the prior art, there is a measurement method of the optical Gouy phase parameter, and the value of the Gouy phase parameter is obtained by detecting two beams of optical coherent signals. For example, the paper "Supercontinuum Interferometry The coherent method is used in "Measurement of Gouyi Phase Shift", although this method has certain advantages, but there are essential deficiencies. The positioning requirements of the optical and optical-mechanical structures are high, and the anti-interference of the system is not strong; it is impossible to achieve high-sensitivity direct measurement of any optical Gouy phase parameters, and it is impossible to realize the measurement of Gouy phase parameters in high numerical aperture optical systems

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