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Proceedings Paper

Attenuation of midinfrared free electron laser energy with eyewear
Author(s): Karen Margaret Joos M.D.; William Gabella
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Paper Abstract

Purpose: To determine the attenuation of free electron laser (FEL) energy at several wavelengths through microscope objective and eyeglass lenses. Materials and Methods: The FEL at wavelengths of 2.3 um, 2.5 um, 3.0 um, 3.5 um, 4.0 um, 4.5 um, 5.0 um, 6.45 um, 7.0 um, 7.5 um, and 8.0 um was telescoped using a 500 mm nominal focal length lens and a 200 mm focal length lens. The beam had a final spot of about 3 mm and was passed through a 3 mm aperture and onto the 8 mm active area of a J9LP Molectron detector. The eyeglass sample was placed 3 cm in front of the detector. Energy readings were averaged over multiple pulses. Results: Attenuation varied greatly with wavelength and sample from a low attenuation of 0.46 dB, 90% transmission, for short wavelengths through common glass to greater than 60 dB attenuation (transmission at the detector noise level) for IR safe glass by Aura, Inc. Conclusion: Only the designated laser safety goggles effectively attenuate free electron laser energy at 2.3 um and 2.5 um. A microscope objective lens, polycarbonate, and silica glass eyewear is capable of effectively attenuating FEL energy at wavelengths greater than 4.5 um, but the polycarbonate lenses demonstrated material damage.

Paper Details

Date Published: 18 April 2005
PDF: 7 pages
Proc. SPIE 5688, Ophthalmic Technologies XV, (18 April 2005); doi: 10.1117/12.596606
Show Author Affiliations
Karen Margaret Joos M.D., Vanderbilt Univ. (United States)
William Gabella, Vanderbilt Univ. (United States)

Published in SPIE Proceedings Vol. 5688:
Ophthalmic Technologies XV
Fabrice Manns; Bruce E. Stuck; Michael Belkin M.D.; Per G. Söderberg; Arthur Ho, Editor(s)

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