An apparatus which can be referred to as a Virtually Imaged Phased Array (VIPA). The apparatus receives an input light and produces a spatially distinguishable output light in accordance with the wavelength of the input light. The apparatus includes first and second surfaces separated from each other...http://www.google.ca/patents/US5969866?utm_source=gb-gplus-sharePatent US5969866 - Virtually imaged phased array (VIPA) having air between reflecting surfaces
