The 10Z20DM.5 Laser Line Dielectric mirror is a highly efficient reflector optimized for a narrow 488-514.5 nm wavelength range. This 1 inch (25.4 mm) diameter mirror is made from a 6.0 mm thick Zerodur substrate. Zerodur is a glass-ceramic material where thermal expansion is nominally zero. This extra stability can be critical for applications requiring diffraction limited performance. The DM.5 coating is designed for use with Argon-Ion lasers and has a center wavelength of 488 & 514.5 nm. The coating achieves greater than 99% reflectance, from 0–45° angle of incidence, for any polarization. This multilayer dielectric coating is extremely durable, making it resistant to damage from repeated cleaning. This mirror has a λ/10 surface flatness and a 15-5 surface quality.