Thermal lens spectrometry: Optimizing amplitude and shortening the transient time
| Autor: | Marcos A. C. de Araújo, P. Alcantara, Rubens Silva, Sanclayton G. C. Moreira, Paulo C. de Oliveira, Pedro Jali |
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| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Materials science
business.industry General Physics and Astronomy Thermal diffusivity Beam parameter product Laser flash analysis lcsh:QC1-999 law.invention Lens (optics) Amplitude Optics law Physics::Accelerator Physics Laser beam quality Transient (oscillation) business Beam (structure) lcsh:Physics |
| Zdroj: | AIP Advances, Vol 1, Iss 2, Pp 022154-022154-12 (2011) |
| ISSN: | 2158-3226 |
| Popis: | Based on a model introduced by Shen et al. for cw laser induced mode-mismatched dual-beam thermal lens spectrometry (TLS), we explore the parameters related with the geometry of the laser beams and the experimental apparatus that influence the amplitude and time evolution of the transient thermal lens (TL) signal. By keeping the sample cell at the minimum waist of the excitation beam, our results show that high amplitude TL signals, very close to the optimized value, combined with short transient times may be obtained by reducing the curvature radius of the probe beam and the distance between the sample cell and the detector. We also derive an expression for the thermal diffusivity which is independent of the excitation laser beam waist, considerably improving the accuracy of the measurements. The sample used in the experiments was oleic acid, which is present in most of the vegetable oils and is very transparent in the visible spectral range. |
| Databáze: | OpenAIRE |
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