The word dichroic is usually used about
mirrors or colour
filters that is
transparent to some colour
wavelengths but
reflective to others.
The most common,
widespread use of dichroic materials is in the
halogen dichroic lamp used in
spotlights. These lamps have a
reflector that is
reflective to
visible light but transparent
to
infrared wavelengths.
Dichroic filters is also used in
photography(for example
dichroic heads in photographic printers) and in high quality
digital cameras to
split up the pictures in to their
individual colour components before it is 'read' by
CCD imagesensors.