Damage Threshold Studies in Laser Crystals: Self-Focusing Experiments and Electron Heating Theory
Semiannual rept. no. 4,
HUGHES RESEARCH LABS MALIBU CA
Pagination or Media Count:
Details of the temporal development of damage tracks are presented and discussed in terms of a self-focusing theory. The results of a number of streak camera photographs show that the damage track grows in a way which depends on the temporal behavior of the leading edge of the incident pulse. This work constitutes the first direct evidence for a moving self-focus in solids. A comparison with self-focusing theory is given and the importance of electrostriction is made evident. Damage thresholds in sapphire for lenses of different focal length are presented and compared with the results obtained for ruby in the last report. Also in this report damage with cylindrical lenses is discussed. An observation of rings in the beam profile of the focused laser beam is presented. The phenomenon which appears at points beyond the beam waist is a property of the ruby laser or possibly a combination of the laser and the lenses. This behavior could well be a general property of single mode solid state lasers. Further theoretical effort has been devoted to the problem of heating of electrons in polar crystals by intense optical fields. A kinetic equation has been developed which appears to offer a basis for settling the question of electron heating.
- Lasers and Masers
- Radioactivity, Radioactive Wastes and Fission Products
- Solid State Physics