Reflective two-dimensional spatial light modulators

A method of fabricating a two-dimensional (2D) Micro-Electromechanical System (MEMS) light modulator, comprising:

• forming a substrate reflector including a static reflective surface formed over a surface of a substrate;
• forming a patterned sacrificial layer over the substrate reflector and surface of the substrate, the patterned sacrificial layer having a predetermined thickness and including a number of post openings extending through the patterned sacrificial layer to the surface of the substrate;
• forming a number of posts in the number of post openings;
• forming a deformable membrane over the number of posts and the patterned sacrificial layer;
• patterning the deformable membrane to form an electrostatically deflectable patterned central portion (CP) and a number of flexures through which the CP is coupled to the posts;
• forming a membrane reflector including a deformable reflective surface on a surface of the CP;
• and
• removing the patterned sacrificial layer to release the deformable membrane, wherein the CP is separated from the surface of the substrate by a deflection gap equal to the predetermined thickness of the patterned sacrificial layer, and wherein the predetermined thickness is selected so that when the deformable reflective surface is deformed into a non-planar surface by electrostatic deflection of the CP, light reflected from the membrane reflector is brought into phase interference with light reflected from the substrate reflector.

A system comprising:

• a light source operable to generate a light beam;
• a spatial light modulator (SLM) operable to modulate light incident thereon, the SLM including a multi-pixel, array of two-dimensional (2D) Micro-Electromechanical System (MEMS) light modulators, each 2D MEMS light modulator including:
• a deformable membrane suspended over a surface of a substrate by posts at corners thereof, the deformable membrane including an electrostatically deflectable patterned central portion (CP) and a number of flexures through which the CP is coupled to the posts;
• a membrane reflector including a deformable reflective surface formed on a surface of the CP;
• and
• a substrate reflector including a static reflective surface formed on a surface of the substrate below the membrane reflector, and exposed through void spaces between the posts, the number of flexures and the CP, wherein the membrane reflector is separated from the substrate reflector by a deflection gap selected so that when the deformable reflective surface is deformed into a non-planar surface by electrostatic deflection of the CP, light reflected from the substrate reflector is brought into phase interference with light reflected from the membrane reflector when the deformable reflective surface is deformed into a non-planar surface by electrostatic deflection of the CP;
• imaging optics operable to focus modulated light from the SLM onto a focal plane of the system;
• and
• a controller operable to control the light source, SLM and imaging optics to modulate light incident thereon and to focus and scan the modulated light across the focal plane.