• Made of BK7 glass or UV grade fused silica (UV FS)
• Polished to high surface quality (20-10 scratch & dig)
• Limit the transmitted wavefront distortion to λ/10
• Standard substrates are available with a variety of radii of concave or convex curvature

We offer two substrate materials, spanning a range of thermal expansion coefficients. For applications in which thermal shock is absent and thermal stability is not critical, BK7 glass is a suitable and inexpensive material. For applications requiring high thermal stability or involving severe thermal shock, you should choose windows made of UV grade fused silica.