Aberration effects in the interaction of focused laser beams with matter
| Autor: | J. M. Aaron, C Grey Morgan, C L M Ireland |
|---|---|
| Rok vydání: | 1974 |
| Předmět: |
Beam diameter
Acoustics and Ultrasonics Chemistry business.industry Condensed Matter Physics Laser Beam parameter product Surfaces Coatings and Films Electronic Optical and Magnetic Materials law.invention Spherical aberration Optics law M squared Laser beam quality business Beam (structure) Beam divergence |
| Zdroj: | Journal of Physics D: Applied Physics. 7:1907-1917 |
| ISSN: | 0022-3727 |
| DOI: | 10.1088/0022-3727/7/14/309 |
| Popis: | An analysis of the role of primary spherical aberration in governing the intensity distribution of a focused laser beam has been confirmed by recording the fluorescence caused by the passage through a dye solution of radiation from both an Nd3+ laser and an He-Ne laser. The agreement between these recorded distributions and those computed using the Fresnel-Kirchhoff integral leads to the specification of the limit less-than-or-eq, slant 1? for the reliable use of the geometric-optics approximations d=f? and l=2(radical 2-1)f2?/D for the focused beam diameter d and effective length l of the focal volume in terms of the beam divergence ?, unfocused beam diameter D and lens focal length f. Use of these relations under conditions where >1? can lead to grossly inaccurate evaluation of the focal dimensions and of the focused beam intensity. The role of spherical aberration in laser-beam-induced gas breakdown has been investigated experimentally using single 20 ps Nd3+ laser pulses and combinations of beam diameters and lenses which changed from 0?41? to 164?. The results confirm the importance of aberration in controlling the focused beam intensity. The breakdown threshold intensity for argon at atmospheric pressure was found to be 3 ? 1013 W cm?2. |
| Databáze: | OpenAIRE |
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