Solid metal prisms can be useful for turning light through 90 degrees, and can be easier to mount and align than a circular mirror. The prisms in the picture are Copper with our Gold coating & have tapped holes in the base to allow for precise positioning. We have also made prisms from Stainless Steel
We can also use “helicoil inserts” in the threaded holes, to make them robust enough for frequent use.
It is also possible to make the apex of a roof top prism razor sharp, so they can be used as a knife edge, or pick off mirror in high power laser applications such as CO2 or fiber lasers.
Potentially roof top prisms are beam splitters that can be adjusted for splitting ratio by lateral movement, and are polarisation insensitive.
Unlike transmissive beam splitter coatings, the Gold coating works across a broad spectrum of wavelengths from 600nm to 300um wavelength in the Terahertz spectrum.