Anti-Reflection (AR) coating is one of widely used optical thin-film coatings that can be applied to the surfaces of optical elements to reduce reflection and to improve transmittance within some spectral region.  
Single Wavelength AR Coatings 
Substrate Material: fused silica, BK7
Surface Figure: < λ/10 @ 632. 8nm
Surface Quality: 40-20
Chamfer: 0.5mm, 45°
Coating Material: Electron beam deposited dielectric multi-layers
Incident: 0°
Clear Aperture: > Central 85% of diameter