Optical Phase Conjugation and Holography

The characterisation of optical phase conjugation by SBS and its use in high power lasers , is being studied at Adelaide and has already yielded promising results. With the aid of some sophisticated diagnostics including a 2GHz transient digitizer, a novel grating-based Michelson interferometer to monitor coherence length and Mach-Zehnder interferometer to measure phase and amplitude fidelity of the return pulses, phase conjugation has conclusively been observed in both methanol and freon. Attention is now being concentrated on understanding the limitations introduced by short coherence length pulses,and investigating competing processes which reduce the phase conjugate return.

A major project is the development of more compact schemes for the holographic correction of aberrations in large optical elements as pioneered by Professor Munch at TRW. Practical applications of this concept would permit for example the use of large (100m diameter) balloons in space or craters of the moon as structures for the primary collecting element of the next generation of space telescopes. The poor quality of such reflectors could be corrected with realtime active holography, retaining the advantage of their huge light-collecting areas.

The computer-generated holography project is another one that promises important benefits to applications. Currently, large expensive laser installations are required to make holograms, presenting a considerable cost barrier to their wider commercial use in the media. Methods of calculating the interference patterns recorded on a hologram and of directly writing this onto a suitable medium (with optical or non-optical methods) are being developed in the group.

Recent Publications and Reports

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