Richard L. Sutherland - Dayton OH
Lalgudi V. Natarajan - Beavercreek OH
Vincent P. Tondiglia - Dayton OH
Robert L. Crane - Kettering OH
The United States of America as represented by the Secretary of the Air
Force - Washington DC
A new personal laser dosimetry badge records intentional or unintentional exposure to laser radiation. A Fresnel biprism is mounted over a layer of photopolymerizable material, preferably a polymer-dispersed liquid crystal material. A laser beam striking the apex of the biprism splits into two beams crossing at an angle which depends on the prism apex angle and the angle of incidence. These crossed beams form an interference pattern at the photopolymer with bright and dark fringes separated by a distance which depends on wavelength and the crossing angle of the two beams. The light triggers a photopolymerization reaction in the bright regions and records a permanent refractive index modulation, a hologram, which serves as a record of the laser interference pattern. Light incident normally on the badge will produce a normal index grating. Light incident at an angle will produce a slanted grating.