Optical non-linear method for measuring material based on 4f phase coherent imaging system

Abstract

The invention discloses an optical nonlinear method which is based on the measuring materials of a 4f phase and coherent imaging system. The 4f phase and coherent imaging system divides incident laser into two beams through a beam splitting prism; wherein, one beam comes into a measure optical path as a probe light and is collected by a CCD camera after passing 4f system and the other beam is a reference light and is collected by the same CCD camera after coming into a reference light path; samples are arranged at a Fourier plane of the 4f system of the measure optical path. The invention is characterized in that the reference light path is the 4f system; and the outgoing direction of the reference light path and the outgoing direction of the measure optical path are parallel. The improvement of the reference light path leads the invention to get the distribution situation of an incident pulse space on the incident plane at the same time of getting pulsed laser energy on the samples and to measure the nonlinear refractive index under the condition of the unstable spatial distribution of light spots with the simple optical path, the quick testing speed, the accurate results and the convenient data processing.

Description

technical field [0001] The invention relates to a measurement method of photonics nonlinear materials, in particular to a method based on a 4f phase coherent imaging system that can measure the nonlinearity of optical materials under the condition of laser spot distribution and unstable energy, belonging to nonlinear photonics materials and nonlinear optical information processing. Background technique [0002] With the rapid development of optical communication and optical information processing and other fields, the research of nonlinear optical materials is becoming more and more important. The realization of functions such as optical logic, optical memory, optical transistor, optical switch and phase complex conjugation mainly depends on the research progress of nonlinear optical materials. Optical nonlinear measurement technology is one of the key technologies to study nonlinear photonic materials. [0003] The 4f phase coherent imaging system (G.Boudebs and S.Cheruku...

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Problems solved by technology

[0010] However, when the spatial distribution of laser pulses is unstable, due to the instability of the spatial distribution between pulses, the spatial distribution of the nonlinear spot and the linear spot obtained by different pulses on the incident surface may be significantly different. At this time, if you continue to use the linear spot as the input, the numerical simulation results will be different from the experimental measurement results.

Therefore, the existing 4f phase coherent imaging system cannot effectively measure the optical nonlinear refraction of materials when the spot distribution is unstable

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