193nm thin film with low loss and high reflectivity and preparation method thereof

The invention discloses a low-loss and high-reflectivity 193nm thin film and a preparation method thereof. The low-loss and high-reflectivity 193nm thin film comprises a substrate and a thin film, and the thin film is arranged on the substrate; the film system structure is Sub/(HL) n/Air, Sub is a thin film element substrate, Air is emergent medium air, H and L are respectively a high-refractive-index material thin film layer and a low-refractive-index material thin film layer with 1/4 central wavelength optical thickness, and n is the number of film stacks of high-refractive-index materials and low-refractive-index materials. According to the 193nm thin film with low loss and high reflectivity and the preparation method of the 193nm thin film, crystallization of a LaF3 thin film in the 193nm high-reflectivity thin film can be effectively inhibited, so that the roughness of the reflecting film is reduced, the scattering loss is inhibited, and the reflectivity of the thin film is improved; the method has the a