Photochromic polyurethanes for rewritable CGHs in optical testing.

The development of photochromic Computer Generated Holograms (CGHs) to test any complex optics, such as aspheres and free-form optics, is described. A thermally irreversible photochromic polyurethane has been synthesized to give good thin films with a strong modulation of the optical transmission. The photochromic CGH has been tested with a simple interferometrical configuration showing promising results. The use of photochromic CGHs provides advantages over standard technologies, as rewritability and self developing.