OPTICAL ASSEMBLY AND METHOD FOR REDUCING ZERO-ORDER LIGHT IN A HOLOGRAPHIC DISPLAY

An optical assembly is provided for use in holographic display of a replay image. The optical assembly may be of particular use is an augmented reality headset. The optical assembly includes a light-modulation element arranged to be illuminated off-axis by a light beam. The light-modulation element modulates the incident light to generate a replay image and generates a zero-order light beam. A focusing system is arranged after the light-modulation element. A light remover is positioned after the focussing system and is configured to remove the zero-order light beam from the light focussed by the focussing system. The focussing system is configured to focus zero-order light from the light-modulation element in a first plane different from a second plane which is the plane of focus of parallel light of the replay image. The light remover removes the zero-order light in the first plane.