A preparation method of lithium triborate crystal high laser damage threshold anti-reflection coating

Abstract

The invention discloses a preparation method of a nonlinear crystal lithium triborate crystal surface high-laser-damaged-threshold antireflection film. Aiming at high LBO crystal anisotropy and the damage mechanism of the antireflection film, the method includes the steps that the surface of an LBO crystal is plated with a SiO2 film through an IAD process, and the film with which the surface of the LBO crystal is plated through the IAD process carries out plating through a sol-gel method. The LBO antireflection film prepared through the method has excellent optical properties, the high damage threshold and good environmental stability, and can be compatible with existing substrate machining, cleaning and film preparation processes. The preparation method has the beneficial effects of being high in process repeatability, high in controllability, easy to popularize and the like, and has wide application prospects in the field of high-power laser films in future.

Description

technical field [0001] The invention relates to a preparation method of an optical thin film, in particular to a preparation method of a non-linear crystal lithium triborate crystal (LBO) high laser damage threshold anti-reflection film. Background technique [0002] In a strong laser system, the powerful laser energy can easily cause damage to the components in the system, so there is a high requirement for the gain medium to resist laser damage. Lithium triborate (LBO) crystal has the advantages of high damage threshold, large nonlinear coefficient, large phase matching range, wide acceptance angle, and small dispersion angle. It has received extensive attention and research in recent years, and has been successfully applied to high-power In the laser system, it is used as the core component of frequency doubling conversion and optical parametric amplification. The LBO crystal has a large refractive index, and when the laser is incident, it will produce strong Fresnel ref...

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Problems solved by technology

However, the single-layer chemical film cannot guarantee the high transmittance of the dual-band, so the use result is not ideal, and the two-layer chemical film will directly fall off in a large area at the end of the plating due to the inability to solve the problem of stress matching.

Another disadvantage of the chemical film is that it is usually relatively loose. After a period of use, the substrate will absorb moisture due to water vapor erosion, resulting in a decrease in the performance of the film, or even a complete shedding, and a short service life. Afterwards, the substrate needs to be reprocessed to deposit the film again. , but repeated processing will shorten the service life of the LBO crystal substrate

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