Nonlinear absorption measuring method based on lens geometric optical imaging

Abstract

The invention discloses a method for measuring nonlinear absorption based on geometric optical imaging of a lens. Light output by a laser is divided into monitoring light and detection light; the monitoring light is received by an energy meter probe and is used for monitoring the energy transmitted on a sample to be tested in a real-time mode; the detection light is focused by a focusing lens andthen irradiates on the sample to be tested positioned at a focus or the nearby position of the focusing lens; the non-linearity leads the space distribution of the detection light which passes through the sample to change; and the change is recorded by a CCD camera through an imaging lens arranged at the rear position. A theoretical model of a measurement system which works according to the method is simple; and the method has the advantages that the method has easy data processing and quick measurement speed, reduces optical accumulation effect by single pulse measurement, has low sensitivity to the random fluctuation of laser beams, and has accurate measurement results as well as intuitive and clear experimental results, the measurement of non-linear absorption is not affected by non-linear refraction, and so on.

Description

Technical field [0001] The invention relates to a measuring method for measuring nonlinear photonics materials, in particular to an imaging method for studying nonlinear absorption, belonging to the field of nonlinear photonics materials and nonlinear optical information processing. Background technique [0002] With the rapid development of technologies in the fields of optical communication and optical information processing, the research of nonlinear optical materials has become increasingly important. Optical information storage, optical switches, optical computers, laser processing, laser medical treatment and photon biology, laser detection and metrology, laser spectrum analysis technology, laser weapons, etc. all depend on the research progress of nonlinear optical materials. Optical nonlinear measurement technology is one of the key technologies for studying nonlinear optical materials. At present, the commonly used methods for measuring nonlinear optical parameters incl...

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Problems solved by technology

[0005] Since the optical field distribution is affected by both nonlinear absorption and refraction, the 4f system is used to measure samples with pure nonlinear refraction with high sensitivity, but there are certain limitations in measuring samples with nonlinear absorption

Although the value of nonlinear absorption can be extracted by numerical calculation (LI YunBo, SONGYingLin, WANG YuXiao, ZHANG XueRu, SUN JiangQin, YANG JunYi, SHIGuang & WANG Yu, "Simultaneous measurements of nonlinear reflection and nonlinear absorption using a 4f imaging system" ( 2008)), but can not get very intuitive results, and the data processing is more complicated

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