Hot & Cold Mirrors
Hot
and cold mirrors limit
the spectral transmittance of an optical system. They operate by means of
dichroic reflection of a thin film deposited onto a thin glass substrate.
Various types of mirror are available as including hot mirrors (which
reflect infra-red while transmitting visible) ) cold mirrors (which transmit
infra-red while reflecting visible) and UV cold mirrors (which transmit
visible and infra-red, while transmitting ultra-violet).
It is important to specify whether these are to be used at normal or
45degree angle of incidence.
Standard filters are circular (12.7
or 25.4mm diameter) or square (50.8 x 50.8 mm) in shape. Thickness usually
about 3 mm.