Investigation of material damage
Abstract
This report describes work performed in a continuing program of investigations on the mechanisms by which high power pulsed CO2 laser radiation interacts with target surfaces. The experimental work has been performed using a pulsed CO2 TEA laser capable of delivering up to ten to the 9th power w/sq cm to the target surface in a pulse of duration around 100 nanoseconds. Results described in this report include the following: (1) Measurement of the pressure pulse induced in target materials by the laser pulse. Measurements were obtained as a function of target material, thickness, ambient air pressure, laser power density, and interpulse time. For metals, a typical value of peak shock pressure is around 100 bars at a laser power density around 1.5 x ten to the 8th power/sq cm at 1 atmosphere ambient pressure. For alkali halides, the results can be related to material damage. (2) Characterization of the target surface, by Auger spectroscopy and by measurements of surface scattering to determine the spectral density function. (3) Determination of the fraction of laser energy coupled into the blowoff material as a function of laser power density. (4) Construction of apparatus to determine total reflectivity as a function of time during the laser interaction.
- Publication:
-
Interim Report
- Pub Date:
- February 1977
- Bibcode:
- 1977hcms.reptQ....R
- Keywords:
-
- Carbon Dioxide Lasers;
- Radiation Damage;
- Targets;
- Interferometers;
- Laser Damage;
- Quantitative Analysis;
- Surface Layers;
- Lasers and Masers