Z-scan optical nonlinear measuring device and method

Abstract

The invention relates to a Z-scan optical nonlinear measuring device and method. The device and the method can be used for measuring the wavelengths of two lasers, wherein light sources can be continuous light or pulsed light, the pulse width and the repetition frequency are adjustable, and the incident laser power is continuously adjustable from 0 to 100%. According to the device, an optical isolator can be used for effectively eliminating the influence of surface reflection of an optical element and a to-be-measured sample to a laser so as to ensure that a measuring result is accurate and reliable; a lambda / 4 wave plate is rotated to measure nonlinear optical parameters of the sample under the action of lasers in linear polarization, circular polarization and elliptical polarization states; light paths are adjusted to change the relative intensity of the two beams of light so as to implement two-tone time-resolved nonlinear absorption and refraction measurement; and the polarization states of pump light and probe light can be adjusted to measure the time response characteristics of the sample under the action of the lasers in the different polarization states. The device and the method can be used for measuring data of transmission openings, transmission closed holes and reflection openings simultaneously, thus being suitable for measurement of transparent samples and semitransparent samples.

Description

technical field [0001] The invention relates to nonlinear optics, in particular to a Z-scan optical nonlinear measurement device and method for measuring the nonlinear absorption coefficient and nonlinear refractive index of transparent samples and translucent samples. Background technique [0002] The third-order optical nonlinearity of the material makes the refractive index and absorption coefficient proportional to the light intensity. Using this nonlinear effect, real-time dynamic all-optical switches, optical transistors, optical limiters and optical bistable devices can be prepared and applied to optical Super resolution. Using the nonlinear effect of materials, the measurement of nonlinear optical parameters is very critical. Traditional methods for measuring optical nonlinearity include nonlinear interference, degenerate four-wave mixing, near-degenerate three-wave mixing, ellipsometry and beam distortion measurement. The first four methods have high measurement s...

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Problems solved by technology

[0004] However, the existing Z-scan method is not suitable for the optical nonlinear measurement of translucent or opaque samples, especially for semiconductor thin films with strong linear absorption, the spatial distribution of reflected light on the surface will change due to Kerr nonlinearity and thermal expansion, which is impossible Ignore sample reflected light information (see Petrov, D.V.; Gomes, A.S.L.; Arabjo, C.B.d., Reflection z-scantechnique for measurements of optical-properties of surfaces. Appl. Phys. Lett. 1994, 65(9), 1065-1067.)

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