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dc.contributor.advisorSupradeepa, V R
dc.contributor.authorPanda, Binodbihari
dc.date.accessioned2021-01-05T10:08:42Z
dc.date.available2021-01-05T10:08:42Z
dc.date.submitted2020
dc.identifier.urihttps://etd.iisc.ac.in/handle/2005/4793
dc.description.abstractOver the past few decades, applications of high-power fiber laser in the area of material processing, medicine, defence, high precision micro-machining etc., is rapidly increasing. The primary reason behind thriving applications is the exceptional power scaling which is due to unique advantages like better thermal management, compact size, cost effectiveness, high quantum efficiency and excellent beam quality. High power fiber laser has a gain medium which is a long cylindrical geometry of optical fiber and thus, provides a high surface to volume ratio. The heat generated during lasing is distributed over longer fiber length and provides better thermal management as compared to other solid-state and gas-based lasers. However, power scaling of high-power fiber lasers has required the use of Large Mode Area(LMA) fibers to increase the dimension of gain medium(fiber core) to accommodate more power. The excitation mechanism of those lasers is also becoming more complex, which is leading to the presence of higher order waveguide modes supported by these larger fibers in the output beam profile. Therefore, the measurement of the beam quality of the laser (represented by the parameter M2 ) is imperative. Conventional M2 measurement methods such as moving knife-edge, variable aperture, moving slit method etc. uses CCD, CMOS or InGaAs detectors and these detector-based methods are not reliable at high power, because of their very low saturation powers. Therefore, with these measurement techniques, high-power beams need to be attenuated and this attenuation has the potential for substantial distortion of the inherent beam profile thereby degrading the beam quality. Other methods using modal decomposition of different constituent eigenmodes are also suggested to measure M2. However, they are complex and not very accurate. In this work, a high power 100Watt Ytterbium doped fiber laser is built, and its beam profile is characterized with a newly proposed method. A simple, cost-effective and alternative thermal imaging-based measurement technique is implemented to measure both beam profile and beam quality of high-power laser beam at full power without additional attenuation or beam diversion. This technique is wavelength agile, robust and can be easily implemented in any high-power laser laboratory where the thermal camera is readily available.en_US
dc.language.isoen_USen_US
dc.rightsI grant Indian Institute of Science the right to archive and to make available my thesis or dissertation in whole or in part in all forms of media, now hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertationen_US
dc.subjectBeam quality, Beam Profile, High power laseren_US
dc.subjectBeam qualityen_US
dc.subjectBeam Profileen_US
dc.subjectHigh power laseren_US
dc.subject.classificationResearch Subject Categories::TECHNOLOGY::Electrical engineering, electronics and photonics::Photonicsen_US
dc.titleA simple method for measurement of high power, inline beam quality of high-power lasersen_US
dc.typeThesisen_US
dc.degree.nameMTech (Res)en_US
dc.degree.levelMastersen_US
dc.degree.grantorIndian Institute of Scienceen_US
dc.degree.disciplineEngineeringen_US


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