High temperature measurements of reflectivity and heat capacity of metals and dielectrics at 1064 nm
- General Physics Institute of Russian Academy of Sciences, Moscow (Russian Federation); and others
The information on optical and thermal properties of materials at high temperatures is the base for any theoretical analysis of laser matter interaction processes. To evaluate the absolute value of energy deposited in the interaction area and to estimate the laser damage threshold one need possessing the knowledge on reflection/absorption coefficients and heat capacity of material subjected to laser radiation. Because these parameters are strongly dependent on material chemical composition, irradiation and environmental conditions, surface and bulk temperature etc. the task of its direct numerical calculation becomes very difficult and the obtained theoretical estimations are unreliable. Up to now the only way to get the reliable values of the parameters mentioned is the experimental procedure. Among the other experimental techniques developed for measuring reflection/absorption coefficients at high temperatures, the based on an integrating sphere method is the most suitable, reliable and accurate one. The installation for high speed, high temperature measurements of optical (reflectivity) and thermal (heat capacity) properties of metals and dielectric materials is described. The system includes a specially designed photometric sphere (reflected radiation is collected by quartz fibers), a chopped CW Nd:YAG laser with output power up to 250W, which heats samples and simultaneously serves as a probing beam, and a high speed optical pyrometer. The set-up is fully computerised. The real temperature of targets is determined by a simultaneous measuring of brightness temperature and reflectivity at about the same wavelengths. Different metals (iron, different steels, cooper and aluminum alloys, etc.), ceramics (SiC, AlN, Al{sub 2}O{sub 3}), laser active media - Al{sub 2}O{sub 3}: Ti{sup 3+} single crystals, and diamond CVD films have been investigated in air, vacuum and argon atmosphere at heating rates of 10{sup 3} -10{sup 4} K/sec.
- Research Organization:
- International Society for Optical Engineering, Washington, DC (United States)
- OSTI ID:
- 552261
- Report Number(s):
- CONF-961070-Vol.2966; CNN: Project FKZ 13N 6592 2; Project AKZ 0214/95; TRN: 98:009069
- Resource Relation:
- Conference: 28. annual symposium on optical materials for high power lasers - Boulder damage symposium, Boulder, CO (United States), 7-9 Oct 1996; Other Information: PBD: [1997]; Related Information: Is Part Of Laser-induced damage in optical materials: 1996. Twenty-eighth annual Boulder damage symposium, proceedings; Bennett, H.E.; Guenther, A.H.; Kozlowski, M.R.; Newnam, B.E.; Soileau, M.J. [eds.]; PB: 686 p.
- Country of Publication:
- United States
- Language:
- English
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