Method for finely regulating and controlling second-order nonlinear optical process

Abstract

The invention discloses a method for finely regulating and controlling a second-order nonlinear optical process through artificial microstructure design. According to the traditional quasi-phase matching (QPM) theory, phase matching is provided for a nonlinear process by designing an optical superlattice, wherein the period of the optical superlattice is determined by wave vector mismatch in the nonlinear process. Theoretical calculation shows that the method cannot strictly ensure the unidirectionality of energy and phase transformation in a nonlinear process, a significant error can be generated under the condition of high conversion efficiency, and the harmonic phase is difficult to regulate and control during phase matching. According to the method, the parameter of the relative phasedifference angle is introduced when the superlattice structure is designed, the energy change and the phase change of the frequency doubling wave or the fundamental wave in the nonlinear process can be finely regulated and controlled by selecting the proper relative phase difference angle. The method has important application in the aspect of improving the conversion efficiency of the nonlinear process.

Description

technical field [0001] The invention belongs to the field of nonlinear optics, and in particular relates to nonlinear optical energy control and phase matching technology in artificial microstructure materials, wherein the optical superlattice used can be designed according to preset frequency doubled waves and fundamental frequency waves. Background technique [0002] Nonlinear optics is an important field in modern optics, and it is a discipline that studies the interaction between strong light and medium. Second-order nonlinear optical effects such as frequency doubling, sum frequency, and difference frequency have always been the focus of attention in this field. Using the second-order nonlinear coefficients of natural nonlinear materials, second-order nonlinear processes such as frequency conversion can be realized. However, the phase mismatch due to the dispersion of the materials reduces the conversion efficiency. Taking frequency doubled light as an example, Δk=k ...

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Problems solved by technology

[0010] In order to solve the problem that the traditional QPM and RQPM methods cannot continuously control and simultaneously finely regulate the energy and phase in the nonlinear process, the present invention proposes an improved method, and the specific improvement scheme is as follows:

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