Laser Imaging With a Holographically Produced Lens

A process is outlined by which a hologram has been produced for use as an imaging device in a laser machining apparatus. Such a hologram has been termed a hololens. The hololens was initially produced by recording the interference between a coherent plane reference wave and an object wave which was produced by passing a plane wave through a transparency. The recording film was positioned at Brewster\u27s angle and the laser light was polarized normal to the surface of the glass plate substrate in order to reduce optical noise caused by interference between the recording beams and their reflections. This hologram was then replicated on dichromated gelatin to produce a phase hologram of low noise, and diffraction efficiency of 28%. A second hologram of a pattern of spots was produced which delivered 33% of the incident energy to the real image distributed equally to the spots in the pattern. The results appear encouraging for the use of a hololens in laser machining applications