Miniature passively Q-switched lasers and their application to nonlinear frequency conversion in microstructured optical fiber

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Räikkönen, Esa Tapani
dc.date.accessioned 2012-08-23T05:33:26Z
dc.date.available 2012-08-23T05:33:26Z
dc.date.issued 2009
dc.identifier.isbn 978-951-22-9983-6
dc.identifier.isbn 978-951-22-9982-9 (printed) #8195;
dc.identifier.issn 1795-4584
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/4642
dc.description.abstract Laser devices are an integral part of the technological background of our modern society. Laser light transmits data over the fiber-optical cabling of internet, reads DVD disks and bar codes, cuts metals and plastics, etc. Many applications, such as refractive eye surgery, breakdown spectroscopy, and various time-resolved methods, rely on optical power that is delivered in short pulses. The bite of laser light on matter is also greatly enhanced by pulsing. Q-switching is a method of producing pulsed laser light by periodically suppressing the optical feedback of a laser resonator. In passive Q-switching the cycle is run without any external control by the process of saturable absorption. Miniature passively Q-switched lasers are small solid-state devices that produce nanosecond long, kilowatt peak power pulses of coherent light at near-infrared wavelengths. They are simple to fabricate and have found applications, e.g., in range finding, micro machining and spectroscopy. In this thesis the operation of miniature passively Q-switched lasers is studied both theoretically and experimentally. Also, nonlinear frequency conversion of the laser output is applied in microstructured optical fiber. The conversion allows for the laser output to be extended into wavelengths at which no laser sources exist. In miniature lasers the cavity decay time and the thermalization time of the laser multiplets are at close to equal. In order to take this into account, the normalized geometric rate-equation model of passively Q-switched lasers is refined to include the thermalization process. As an experimental case, a high peak power 1123 nm Nd:YAG laser is demonstrated, and the nonsaturable loss level of the Cr:YAG saturable absorber crystal is measured at the laser's wavelength. The output spectrum of a passively Q-switched and frequency-doubled Nd:YAG laser is converted to narrowband visible light ranging from blue to red wavelengths by means of nondegenerate four-wave mixing, and to a broad spectrum of blue light by means of cascaded cross-phase modulation. The output spectra are adjusted by the group-delay profile of the microstructured optical fiber. A broadband source continuously covering the wavelength range of 420-1300 nm is realized by pumping a microstructured optical fiber with a miniature gain-switched Ti:Sapphire laser. en
dc.format.extent Verkkokirja (1718 KB, 76 s.)
dc.format.mimetype application/pdf
dc.language.iso en en
dc.publisher Teknillinen korkeakoulu en
dc.relation.ispartofseries TKK dissertations, 174 en
dc.relation.haspart [Publication 1]: Esa Räikkönen, Scott C. Buchter, and Matti Kaivola. Modeling the time-dynamics of miniature passively Q-switched lasers. IEEE Journal of Quantum Electronics, accepted for publication. en
dc.relation.haspart [Publication 2]: E. Räikkönen, O. Kimmelma, M. Kaivola, and S. C. Buchter. 2008. Passively Q-switched Nd:YAG/KTA laser at 561 nm. Optics Communications, volume 281, numbers 15-16, pages 4088-4091. en
dc.relation.haspart [Publication 3]: E. Räikkönen, S. C. Buchter, and M. Kaivola. 2008. Generation of monochromatic visible light in microstructured optical fiber by nondegenerate four-wave mixing. Applied Physics B: Lasers and Optics, volume 91, numbers 3-4, pages 461-465. en
dc.relation.haspart [Publication 4]: E. Räikkönen, M. Kaivola, and S. C. Buchter. 2006. Compact supercontinuum source for the visible using gain-switched Ti:Sapphire laser as pump. Journal of the European Optical Society - Rapid Publications, volume 1, 06012, 4 pages. © 2006 by authors. en
dc.relation.haspart [Publication 5]: E. Räikkönen, G. Genty, O. Kimmelma, M. Kaivola, K. P. Hansen, and S. C. Buchter. 2006. Supercontinuum generation by nanosecond dual-wavelength pumping in microstructured optical fibers. Optics Express, volume 14, number 17, pages 7914-7923. en
dc.subject.other Physics en
dc.title Miniature passively Q-switched lasers and their application to nonlinear frequency conversion in microstructured optical fiber en
dc.type G5 Artikkeliväitöskirja fi
dc.contributor.department Teknillisen fysiikan laitos fi
dc.subject.keyword solid-state lasers en
dc.subject.keyword Q-switching en
dc.subject.keyword nonlinear fiber optics en
dc.identifier.urn URN:ISBN:978-951-22-9983-6
dc.type.dcmitype text en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.type.ontasot Doctoral dissertation (article-based) en


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