CHARGED PARTICLE EMISSION AFTER RUBY LASER IRRADIATION OF TRANSPARENT DIELECTRIC MATERIALS.
PRINCETON UNIV N J FRICK CHEMICAL LAB
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Ion currents induced by high power laser irradiation of transparent dielectric materials in vacuo below the threshold for physical damage have been investigated. Soft glass, Pyrex, fused quartz, Supracil quartz, CaF2, LiF, and sapphire all show similar behavior. Currents as large as 10 billion ionspulse are obtained using ruby radiation with normal mode power levels of about 200 kW. Both positive and negative ion signals were studied, and for the latter case two distinct signals have been time resolved using Q-switched pulses. The emission is qualitatively similar to related investigations of laser irradiated metal surfaces. These effects are ascribed to laser heating of dust and other surface contaminants with subsequent production of high energy photons and thermionic emission of electrons and ions. The emission of photons, electrons and ions can be reduced, but not completely eliminated, by careful precleaning and repeated lasing on the dielectric surface. Author
- Lasers and Masers
- Nuclear Physics and Elementary Particle Physics