Superimposed fast transient and permanent holographic gratings
Abstract
Abstract A method is disclosed for producing a superimposed fast transient grating on a permanent holographic grating which provides high scattering ability, fast modulation response times, and the capability of writing and erasing signals therein. A glass host is doped with trivalent rare earth ions, and is then placed in the crossed field of two coherent radiation beams to resonantly pump the trivalent rare earth ions at a frequency in resonance with one of the absorption transitions thereof. This produces two types of laser induced gratings, a transient population grating associated with the excited rare earth ions, and a permanent holographic grating associated with a structural modification of the glass host. The superposition of these gratings result in a four wave mixing signal with enhanced strength and the capability of amplitude or frequency modulation. These superimposed gratings have applications involving phase conjugation and other types of optical signal processing and also provide a new method for probing the local structural properties of amorphous materials.
Inventors
- 👤 Richard C. Powell
- 👤 Edward G. Behrens
- 👤 Frederic M. Durville
Bibliographic Details
Claims Analysis
Total Claims: 11References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-01 | 1991-08-31 | 1992-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-01 | 1995-08-31 | 1996-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-01 | 1999-08-31 | 2000-03-01 | $7700.00 | Window Closed / Lapsed |