A kind of cleaning method before coating on lbo crystal surface

Abstract

The invention relates to a method for cleaning LBO crystals before surface coating. The following steps are sequentially conducted on the LBO crystals and include that the surfaces of the LBO crystals are wiped with a mixed solution of absolute ethyl alcohol and diethyl ether; ultrasonic cleaning is conducted on the LBO crystals with a weak alkalinity solution, the weak alkalinity solution comprises NH4OH and H2O2, and the volume ratio of the NH4OH to the H2O2 to the H2O is 1:8:50; the LBO crystals are rinsed with the absolute ethyl alcohol; the LBO crystals are placed in a sealed container containing the absolute ethyl alcohol, and ultrasonic heating cleaning is conducted on the LBO crystals; the LBO crystals are taken out and rinsed again; and a dry nitrogen knife dries the LBO crystals in a positive pressure container environment. Compared with the prior art, the method for cleaning the LBO crystals before surface coating has the advantages of being good in cleaning effect, capable of improving the laser damage resistance of the LBO crystals after the LBO crystals are coated with film and also improving the film adhesive force and anti-crack feature of the LBO crystals after the LBO crystals are coated with the film and the like.

Description

technical field [0001] The invention relates to a laser crystal ultrasonic cleaning method, in particular to a cleaning method before the surface of LBO crystal is coated. Background technique [0002] Lithium triborate crystal (LBO crystal) is an orthorhombic crystal system, which has a very high damage threshold and UV transmittance, and also has a good frequency doubling effect. Therefore, it has broad application prospects in the development of frequency doubling and parametric oscillator devices for high-power lasers, and is currently a commonly used nonlinear optical crystal in high-power lasers. In order to reduce the energy loss caused by the interface Fresnel reflection and improve the operating efficiency of the system, the LBO crystal must be coated with a high-performance laser antireflection film on its surface. However, due to the weak deliquescence characteristics of the LBO crystal and its thermal expansion coefficient Significant anisotropy (α x =10.8×10 ...

AI Technical Summary

Problems solved by technology

Among them, the wiping method is more effective for large-scale particles above microns, but it is difficult to remove sub-micron particles; RCA cleaning belongs to chemical cleaning, which can reduce the adsorption force between particles and the substrate, but if the solubility of the chemical solution is not properly controlled Causes severe corrosion of the substrate, resulting in an increase in surface roughness; ultrasonic cleaning can efficiently remove particles of various sizes from micron to submicron on the surface of the substrate through the selection of ultrasonic cleaning frequency. , will cause physical damage to the substrate surface, these defects will not only seriously affect the optical properties of the substrate but also may lead to catastrophic laser damage

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