Patent ID: 7428085

Claim:
A method of producing a hologram through a two-beam laser interferometric exposure process, said method comprising: emitting a coherent laser light with a laser power of 10 μJ/pulse or more using a solid-state laser as a light source; dividing the pulsed light from said laser into two beams; and conversing the two beam on a surface of or within a workpiece for recording a hologram while controlling said two beams temporally and spatially in such a manner that the respective converged spots of the two beams are matched with one another temporally and spatially to create the interference therebetween so as to record a surface-relief hologram on the surface of the workpiece or an embedded hologram within the workpiece in an irreversible manner, wherein: a femtosecond pulsed laser light is from a mode-lock titanium-sapphire laser serving as said solid-state laser, and the phase compensation of said pulsed laser light is relaxed to allow said laser light to having a pulse width increased up to the range of greater than 900 femtoseconds to 100 picoseconds.