Double-sided optical coating of strongly curved glass by atomic layer deposition

Abstract

A reaction chamber of atomic layer deposition (ALD) was developed for simultaneous coating on the inner and outer surfaces of a large-size and strongly curved glass bowl. The inner surface ALD process was in a showerhead reaction mode and the outer surface ALD process was in a cross-flow reaction mode. Blue reflection (BR) film of 400 nm wavelength and broadband antireflection (BBAR) film of 400-700 nm wavelength were coated on different glass bowls by ALD. The spectral uniformity of both coated bowls was studied. The measured spectra at multiple positions of the glass bowl with the BBAR coating show better spectral uniformity along the circumference than the depth. The spectral deviation is mainly caused by the non-uniformity of the film on the outer surface (