1 July 2014 Laser calorimetric absorptance testing of samples with varying geometry
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Optical Engineering, 53(12), 122503 (2014). doi:10.1117/1.OE.53.12.122503
Abstract
Laser calorimetry is based on the measurement and evaluation of the temperature increase caused by absorption in the sample exposed to laser radiation. A temperature distribution develops in the irradiated sample as a result of dependence on the thermal diffusivity of the sample. Therefore, finding a correlation between the temperature increase and absorption becomes a complex task. This challenge was met by keeping the sample geometry at a standard size and simulating the thermal distribution for a number of optical materials. Using this method, Laser Zentrum Hannover e.V. (LZH) developed a calorimetric test setup that offers fully calibrated absorptance values for sample diameters of 25 mm (or 1 in.) with a total error of below 13% and a relative measurement error of below 5%. However, this technique is limited to the above-mentioned sample geometry. This work presents an approach to adjust the measurement configuration to numerous sample sizes for standard circular laser components. Finite element analysis and experimental verification are presented for exemplary values of the samples’ diameters. Based on the different sample mount concept, this procedure allows utilizing flexibility in test wavelength and angle of incidence, combined with the sensitivity level sufficient for current optical materials.
© 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)
Istvan Balasa, Lars O. Jensen, Detlev Ristau, "Laser calorimetric absorptance testing of samples with varying geometry," Optical Engineering 53(12), 122503 (1 July 2014). http://dx.doi.org/10.1117/1.OE.53.12.122503
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KEYWORDS
Absorption

Sensors

Temperature metrology

Aluminum

Calibration

Coating

Silica

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