Opto Sigma

• Available with highly parallel or wedged faces to reduce ghosts
• Polished both sides to λ/10
• Coating optimized for low loss
• Available with Ultra-Violet grade fused silica and BK7 substrates
• Standard diameters from 25.4 to 50.8mm

These superior beamsplitters are multilayer dielectric coatings on a BK7 or synthetic fused silica substrate. The beamsplitter substrate is polished on both sides to a flatness of λ/10. Substrates can be either precisely parallel to 5arcsec or wedged with a 1 degree angle. The wedge angle eliminates ghost images by bending the beam out of the direction of the principal beam.

Note that when used as intended at 45 degrees these beamsplitters present a smaller cross section to the beam. (The 30mm diameter, 3mm thick size presents a 20mm cross section and the 50mm diameter, 5mm thick size presents a 32mm cross section). The coatings provide approximately equal reflected and transmitted beams with very little absorption loss. However the, p- and s-components are quite different (typically Rp=35% and Rs=65%). Several different coatings are offered from the Ultra-Violet through the visible to the near IR.