Chirp quasi-periodic structure superlattice material and design method thereof

Abstract

The invention discloses a chirp quasi-periodic structure superlattice material and a design method thereof. A common quasi-periodic structure has a plurality of reciprocal lattice vectors in a Fourierinversion space, and each reciprocal lattice vector is in a peak shape with a very narrow width. The phase matching of the peak-shaped reciprocal lattice vector requires that the ambient temperatureand the input laser wavelength are both narrow-band, otherwise, the power stability and efficiency of the frequency conversion of the peak-shaped reciprocal lattice vector fluctuate drastically, and the superlattice material with the periodic structure has higher condition requirements in actual use. According to the embodiment of the invention, the chirp structure is introduced into the design ofthe quasi-periodic structure, and one or more reciprocal lattice vectors are broadened and flattened through a chirp quasi-periodic structure, so that the bandwidths and the strengths of the reciprocal lattice vectors can be controlled at the same time, the frequency conversion bandwidths of quasi-periodic superlattices are improved, the stability of the conversion efficiency is improved, and theharsh environmental requirements of quasi-periodic materials in practical application are reduced.

Description

technical field [0001] The present application relates to the field of superlattice technology, in particular to a chirped quasi-periodic structure superlattice material and a design method thereof. Background technique [0002] Quasi-periodic structures are important structures for multiple quasi-phase matching. The concept of Quasi-Phase-Matching (QPM) was proposed in 1962, nearly 60 years ago. Although the QPM theory was proposed very early, due to the difficulty in the preparation of periodically polarized crystals, it was not until the early 1980s that researchers introduced microstructures into dielectrics and developed a dielectric superlattice (Dielectric Superlattice). Start the experimental exploration of QPM. Since in the dielectric superlattice, the parameter to be periodically modulated is mainly the second-order nonlinear coefficient χ(2), the dielectric superlattice is also called an optical superlattice (Optical Superlattice). Optical superlattice matrix m...

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Problems solved by technology

[0024] This application provides a chirped quasi-periodic structure superlattice material and its design method to solve the problem that quasi-periodic structure superlattice materials in the prior art require relatively harsh conditions in actual use

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