Self-Pumped Phase Conjugation in Barium Titanate with High Intensity Nanosecond Pulses,
IMPERIAL COLL OF SCIENCE AND TECHNOLOGY LONDON (UNITED KINGDOM) BLACKETT LAB
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An investigation of self-pumped phase conjugation in barium titanate is made using nanosecond pulses 15 ns derived from a repetitively pulsed 10 Hz and frequency-doubled NdYAG laser system 532 nm wavelength. It is experimentally shown that high reflectivity 20 can be achieved. It is also shown that there is a progressive decrease in the reflectivity of both the corner-pumped and ring-passive geometries at pulse intensities of 4 MWsq.cm. At these intensity levels a high photo-carrier population is induced, altering the relative concentrations of Fe2 and Fe3 centres and leading to a strong intensity-dependent competition between hole and electron photoconductivity. For the corner-pumped geometry the intensity-dependence of the phase conjugate reflectivity is shown. The reflectivity increases with pulse intensity up to 20. Small change in reflectivity occurs in the range 0.5 to 4 Mcm2 but a dramatic decrease in the reflectivity occurs at intensity 4 MWsq.cm.
- Nuclear Physics and Elementary Particle Physics