Abstract
The preponderance of laser beam shapes cannot be ruled out during the implementation of an optical experiment nor during the formulation of its theoretical background. The present work elucidates the role of Gaussian and top-hat beam shapes in generating and analysing the photothermal beam deflection (PBD) signals. The complex geometrical optics models encompassing the perturbations in the phase and amplitude of the probe beam with one-dimensional (1D) and two-dimensional (2D) approaches is employed to curve fit the PBD signal and are compared. From the fitted curve, the thermal diffusivity and conductivity of the sample are calculated with the 1D and 2D models. A uniform intensity distribution over the sample, like a top-hat beam, is achieved using an optical lens system and verified using a beam profiler. When the phase and amplitude of the PBD signal are fitted at different positions of the lens, i.e., in focussed and defocussed conditions, it is observed that difference in the measured thermal characteristics is about 30% for the Gaussian pump beam profile, whereas it is only <4% for top-hat beam. Even though the fitting accuracy and sum of residues estimated for the 2D model are better than 1D, the ease of computation with the 1D model employing top-hat excitation suggests the application of the top-hat profile in photothermal experiments.
Funder
Slovenian Research Agency
Subject
Radiology, Nuclear Medicine and imaging,Instrumentation,Atomic and Molecular Physics, and Optics
Reference46 articles.
1. Laser Beam Wavefront Correction for Ultra High Intensities with the 200 TW Laser System at the Advanced Laser Light Source;Fourmaux;Opt. Express,2008
2. Samelsohn, G., and Mazar, R. (1995, January 10–14). Adaptive Wavefront Tilt Correction for Imaging and Laser Beam Formation in a Turbulent Atmosphere. Proceedings of the 1995 International Geoscience and Remote Sensing Symposium, IGARSS ’95. Quantitative Remote Sensing for Science and Applications, Firenze, Italy.
3. Dynamic Wavefront Correction of Nd:YAG Lasers by Self-Pumped Phase Conjugation in Photorefractive BaTiO/Sub 3/:Rh;Huot;Proc. IEEE,1999
4. Adaptive Optics in Laser Processing;Salter;Light Sci. Appl.,2019
5. Adaptive Optics Based on Machine Learning: A Review;Guo;Opto-Electron. Adv.,2022
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献