Fused Silica is synthetic amorphous silicon dioxide of extremely high purity. This non-crystalline, colorless silica glass combines a low content of inclusions with high refractive index homogeneity, a very low thermal expansion coefficient, and excellent transmittance in the wavelength regime from UV to NIR. As a result, these mirrors will perform better with temperature fluctuations and is ideal for high-energy laser applications due to its high energy damage threshold. For more information, please see our Optical Materials technical note.

Many standard mirrors are offered with high average reflectivity, but these Supermirrors have exceptional absolute reflectivity specifications of greater than 99.97%. We stock theses mirrors making them the highest absolute reflectivity available in a standard catalog optic. These mirrors are ideal when you need every photon. The high finesse coatings have finesse greater than 10,000 and efficiency greater than 10% when used in carefully constructed cavities.

High finesse mirrors work in a narrow spectral band. For applications that require high reflectivity across a winder band, we offer a more broadband general purpose SuperMirrors. The SB.1 coating boasts reflectivity greater than 99.9% from 485 to 700 nm at 0 to 45 degrees angle of incidence.

This mirror is superpolised to <2 Å RMS microroughness for ultra-low scatterring. 10-5 scratch-dig is achieved in the center 50% of the clear aperture. This central area is the sweet spot where Fabry- Perot cavity designs can achieve extremely high finesse.

Newport's proprietary IBS coating technique enables the SuperMirrors to provide the highest absolute reflectivity available as standard mirrors. IBS is a higher energy coating process in which atoms of the coating material can be packed more tightly. The results are very high reflectivity, resistance to environmental changes, and unmatched performance for intra-cavity mirrors which require high finesse.

Care should be taken to insure that these mirrors remain clean during use to maintain the high reflectivity and performance levels. The only cleaning operation recommended is the removal of dust with a low pressure filtered dry nitrogen nozzle. Cleaning techniques specifically developed for high performance optics may be used by qualified personnel. 100 ppm performance levels cannot be maintained if the optic is cleaned using standard techniques.