High contrast, ultrafast optically-addressed ultraviolet light modulator based upon optical anisotropy
US6366389B1 · kind B1 · utility
Inventors
Key dates
| Filing date | Aug 15, 2000 |
| Grant date | Apr 2, 2002 |
| Priority date | — |
| Expiry date | Aug 15, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/0126
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A high contrast ultrahigh speed optically-addressed ultraviolet light modulator exploits the optical anisotropy in a ZnO film epitaxially grown on (01 {overscore (1)}2) sapphire. This device, which could also be realized in a ZnO bulk crystal or similar wide bandgap material, achieves both high contrast and high speed by exploiting the anisotropic bleaching of the anisotropic absorption and concomitant ultrafast polarization rotation near the lowest exciton resonances produced by femtosecond ultraviolet pulses. The resultant modulation in a preferred embodiment is characterized by a contrast ratio of 70:1, corresponding to a dynamic polarization rotation of 12°, and decays to a quasi-equilibrium value within 100 ps.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.