Laser despeckler based on angular diversity

An illumination device comprising:

• a first transparent substrate having an output surface;
• a variable refractive index layer having an input surface and an output surface,
• wherein said input surface of said refractive index layer overlays
• said output surface of said first transparent substrate;
• a second transparent substrate having an input surface, wherein said input surface of said second transparent layer overlays said output layer of said variable refractive index layer;
• and
• a holographic diffuser,
• wherein said output surface of said variable refractive index layer and said input layer of said second transparent substrate are each configured as a multiplicity of ray deflecting features to deflect incident light into a temporally varying random distribution of ray directions in a first predefined range of angles having a plurality of angles of deflection such that the plurality of angles of deflection are varied as a voltage applied across the variable refractive index is iteratively varied,
• wherein each point in said holographic diffuser diffracts incident light rays of said first predefined range of angles into output light rays having a second predefined range of angles such that a diffuse illumination patch is produced at any surface intercepting said output light rays.