Diagnostics and Storage of Turbulence Distorted Wavefronts by Using Spectral Hole Burning Materials
Abstract
SRI International has completed a program of research on an innovative time-differential phase sensor suitable for detecting the fast changing structure within airborne turbulence. This innovation is based on an original incorporation of time-domain-stimulated photon echo into a phase-conjugate-mirror of an optical novelty filter setup. The unique advantage of this photon echo novelty filter is that its fast response time is completely programmable through external excitation timing. Therefore, it has an outstanding potential for tracking fast changing phase distortions in real time. Using Eu and Pr doped yttrium silicate crystal as the hole-burning materials for the stimulated photon echo, we demonstrated the concept and basic performance of the photon echo novelty filter. The sensitivity of the filter to a sudden change of optical path length is measured to be better than 0.05 wavelength (^ 0.6 microns). The fast temporal tracking ability of the filter is proved by its accurate measurement of phase modulation events from a nanosecond through microsecond time scale. The filter's holographic memory and time-differential processing of nonuniform phase-only distortion is proved. Our results show that the photon echo novelty filter is well worth further investigation and development into a powerful sensor of the temporal and spatial structures of airborne turbulence.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1998
- Accession Number
- ADA351776
Entities
People
- Ravinder Kachru
- Yiping Zhang
Organizations
- SRI International