A system for directing incident light onto spatial light modulator planes

A first optically active area 601 and a second optically active area 602 of first and second respective spatial light modulator (SLM) planes are configured to receive first and second respective optical signals from an optical system. Light is directed toward the first and second optically active areas from a first and a separate second direction of the optical system by a first reflector 603 and a respective second reflector 604 which overlay the active areas at an angle. The first and second SLM planes may be parallel to an optical axis plane of the optical system and may form a SLM device. The active areas may be programmable deflection or attenuation planes and coplanar. The first and second reflectors may comprise 45o reflecting surfaces. The incidence normal of the first and second SLM planes may be within the same hemispherical angular area. The centre of the first and second reflectors and the optical axis of the optical system may be in the same plane. There may be a third SLM plane with a third optically active area 605 and a third reflector 606. The optical system may be a switch to direct optical signals to first and second reflectors.