The gobo may include a plurality of mutually superimposed disc-shaped and transparent substrates (1, 2, 3, 4) and each of the substrates may include a dichroic surface coating so as to form a colour filter.

Two years after starting his development work, he made contact with a German company that specialises in dichroic colour coating of glass.

Only UV energy is reflected, while infrared energy (i.e. heat) is transmitted via the dichroic coating to the extruded section, which is efficiently water cooled.

Frequency-doubled radiation generated on both forward and reverse passes of fundamental laser-radiation through the optically-nonlinear crystal is coupled out of the resonator by the dichroic coated birefringent filter.

For multi-spectral applications, channel separation can be customised by adjusting the dichroic coating of the prisms.

The optical filter is a dichroic coating which separates light into different colors.

The optical filter is located on a light transmissive surface (41b, 51b) of a color splitting device such as a Philips prism (44, 54).