Enhanced vacuum laser-impulse coupling by volume absorption at infrared wavelengths
| Autor: | George W. York, T. Shimada, R. F. Harrison, T. P. Turner, L. C. Haynes, H. S. Steele, Claude R. Phipps, T. R. King, X. F. Corlis |
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| Rok vydání: | 1990 |
| Předmět: |
Materials science
Infrared business.industry Far-infrared laser Infrared spectroscopy Impulse (physics) Condensed Matter Physics Laser Atomic and Molecular Physics and Optics law.invention Wavelength Optics law Thermal infrared spectroscopy Electrical and Electronic Engineering business Coupling coefficient of resonators |
| Zdroj: | Laser and Particle Beams. 8:281-298 |
| ISSN: | 1469-803X 0263-0346 |
| DOI: | 10.1017/s026303460000803x |
| Popis: | We report measurements of vacuum laser impulse coupling coefficients as large as 90 dyne/W, obtained with single μs-duration CO2 laser pulses incident on a volume-absorbing, cellulose-nitrate-based plastic. This result is the largest coupling coefficient yet reported at any wavelength for a simple, planar target in vacuum, and partly results from expenditure of internal chemical energy in this material. Enhanced coupling was also observed in several other target materials that are chemically passive, but absorb light in depth at 10-μm and 3-μm wavelengths. We discuss the physical distinctions between this important case and that of simple, planar surface absorbers [such as metals] which were studied in the same experimental series, in light of the predictions of a simple theoretical model. Ablation parameters for use with the model were determined in separate experiments near threshold in air and in vacuum. The transition from volume- to surface-absorption behavior in the infrared is described as being controlled by fluence-limiting and wavelength conversion in the uppermost target layer. |
| Databáze: | OpenAIRE |
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