Selenium gallium lithium middle-far infrared nonlinear optical crystal and preparation method and application thereof

Abstract

The invention relates to a selenium gallium lithium mid-far infrared nonlinear optical crystal and a preparation method and application thereof. The chemical formula of the crystal is LiGaSe2, the molecular weight is 469.16, the crystal is crystallized in a tetragonal system, the space group is a non-centrosymmetric space group I2d, and the cell parameters are as follows: a = 5.843 (2), b = 5.843 (2), c = 10.614 (8), alpha = beta = gamma = 90 degrees, Z = 2, and V = 362.4 (4) 3. The material is prepared by adopting a high-temperature melt spontaneous crystallization method or a Bridgman-Stockbarger method, is structurally composed of [LiSe4] and [GaSe4] tetrahedron elements, and can be used for preparing infrared band laser frequency conversion, infrared laser guidance, infrared laser radar, energy detection, long-distance laser communication and the like. The obtained selenium gallium lithium middle and far infrared nonlinear optical crystal has excellent optical performance (long infrared absorption edge and large nonlinear coefficient). The method has important application value in an infrared laser system.

Description

technical field [0001] The invention relates to a mid-to-far infrared nonlinear optical crystal of lithium selenium gallium and its preparation method and application, belonging to the field of infrared nonlinear optical crystals Background technique [0002] As a frequency conversion device in solid-state lasers, nonlinear optical crystals have attracted extensive attention from scholars in the field of lasers. Among them, infrared nonlinear optical crystals play an important role in practical applications, such as laser orientation, resource detection and long-distance laser communication. Traditional nonlinear optical crystals such as borate (β-BaB 2 o 4 (BBO), LiB 3 o 5 (LBO), CsLiB 6 o 10 (CLBO), KBe 2 BO 3 f 2 (KBBF)), phosphate (KH 2 PO 4 (KDP), KTiOPO 4 (KTP)) are widely used in the ultraviolet and visible light ranges, but their small nonlinear coefficients and short infrared cut-off edges in the mid-to-far infrared band limit their application in the mi...

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Problems solved by technology

Traditional nonlinear optical crystals such as borate (β-BaB 2 o 4 (BBO), LiB 3 o 5 (LBO), CsLiB 6 o 10 (CLBO), KBe 2 BO 3 f 2 (KBBF)), phosphate (KH 2 PO 4 (KDP), KTiOPO 4 (KTP)) are widely used in the ultraviolet and visible light ranges, but their small nonlinear coefficients and short infrared cut-off edges in the mid-to-far infrared band limit their application in the mid-to-far infrared band.

The current commercial infrared nonlinear optical crystals are AgGaS 2 , AgGaSe 2 and ZnGeP 2 etc. This type of material has a large nonlinear optical effect and a wide transmission window, but due to its own inherent defects, such as low laser damage threshold and serious two-photon absorption near 1 μm, it is not suitable for the current high-power laser The application in the output field is limited, and it can no longer fully meet the needs of the current laser technology development. It is urgent to develop and design new infrared nonlinear optical crystal materials with large frequency doubling, wide band and high laser damage threshold.

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