Laser line dielectric mirrors are highly efficient reflectors optimized for a narrow wavelength range. They offer greater than 99% reflectance, from 0° to 45° angle of incidence, for any polarization. Their coatings are very durable, making them easier to clean repeatedly and more resistant to laser damage. Our standard dielectric mirrors utilize Borofloat 33, an excellent general purpose substrate. When high thermal stability is required, Zerodur mirror substrates should be considered because of their nearly zero coefficient of thermal expansion. And for the most demanding Nd:YAG and Excimer laser applications, mirrors with UV fused silica substrates and ultra-hard dielectric coatings have been designed specifically with high damage thresholds.