Efficient holograms and method for making same
US4799746A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 27, 1985 |
| Grant date | Jan 24, 1989 |
| Priority date | — |
| Expiry date | Feb 27, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S359/90
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Light sensitive recording medium is exposed to highly absorbed incoherent light either before or after a slant fringe hologram is recorded therein to reduce the sensitivity of the medium at surface regions adjacent a supporting substrate. The fringes recorded in the area of reduced sensitivity have lower contrast than those recorded in the remainder of the medium, freeing the fringes from the substrate and allowing greater expansion of the medium during a subsequent chemical swelling process. The increased swelling amplifies the refractive index modulation in the medium to increase the diffraction efficiency of the hologram. Dye may be added to the medium to increase absorbance of the incoherent light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.