Hydrophobic antireflective film with high damage threshold based on glancing angle deposition

The spectroscope is a key component in astronomical telescopes and include an antireflective coating on the back. Astronomical equipment are generally located in environments that are susceptible to dust and humidity, as well as variable temperature and humidity conditions. Because of the unique properties of the membrane layer control technology utilized to prepare broadband antireflective films, specific protective measures must be adopted. We designed and fabricated a variable-refractive-index antireflective film and deposited HP1 material on the film surface as an antifog measure. The surface of the antireflective film treated with HP1 was not affected by the antireflection effect, and the spectral performance was stable during testing. In the static water contact angle test, the antifog film treated with HP1 showed good hydrophobic properties, and the antifog effect was excellent in the freezer test. In testing the laser damage threshold, the laser induced damage threshold of the antireflective film at 1064 and 532 nm are 45 and 16.8 J/cm2, respectively, the antireflective film treated with HP1 had almost no effect on the damage threshold of the thin film. The findings of this study provide a good direction for the practical application of variable-refractive-index films and cost reduction in laser systems.