Measurement of sensitivities for the thermal recording of laser beams

Prasad, CR and Nirmala, KA and Venkatesh, Prabha (1985) Measurement of sensitivities for the thermal recording of laser beams. In: Optics & Laser Technology, 17 (6). 297 -302.

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Abstract

A simple technique for determining the energy sensitivities for the thermographic recording of laser beams is described. The principle behind this technique is that, if a laser beam with a known spatial distribution such as a Gaussian profile is used for imaging, the radius of the thermal image formed depends uniquely on the intensity of the impinging beam. Thus by measuring the radii of the images produced for different incident beam intensities the minimum intensity necessary (that is, the threshold) for thermographic imaging is found. The diameter of the laser beam can also be found from this measurement. A simple analysis based on the temperature distribution in the laser heated material shows that there is an inverse square root dependence on pulse duration or period of exposure for the energy fluence of the laser beam required, both for the threshold and the subsequent increase in the size of the recording. It has also been shown that except for low intensity, long duration exposure on very low conductivity materials, heat losses are not very significant.

Item Type:	Journal Article
Publication:	Optics & Laser Technology
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	laser;thermographic recording;carbon photographic paper.
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	19 Jan 2010 09:23
Last Modified:	19 Sep 2010 05:47
URI:	http://eprints.iisc.ac.in/id/eprint/23757

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