{"title":"Shaping a focused laser beam by continuous wavefront control using a deformable mirror","authors":"G. Yoon, T. Jitsuno, M. Nakatsuka, Y. Kato","doi":"10.1364/nao.1997.tua.4","DOIUrl":null,"url":null,"abstract":"Uniform irradiation of laser beam is needed for the directly driven inertial confinement fusion, laser-chemistry and industrial applications such as laser welding, semiconductor processing and laser microfabrication. For improving the irradiation uniformity on a fusion target, several beam smoothing techniques such as a random phase plate (RPP)1, induced spatial incoherence (ISI)2, smoothing by spectral dispersion (SSD)3 and kinoform phase plate (KPP)4 have been proposed. The RPP has energy loss of ~ 15 % by a large diffraction angle, and the ISI and the SSD have imprint problems by instantaneous speckle pattern. The precise KPP with a continuous phase distribution is difficult to fabricate, even if the energy loss can be reduced to 5%. We are developing an active optical system to compensate (or control) a wavefront aberration included in a large-scale laser system for fusion. Shack-Hartmann wavefront sensor using a large F-number plastic micro-lens array5 and continuous faceplate type deformable mirror6 have been developed and their good performance has been demonstrated.","PeriodicalId":135541,"journal":{"name":"Nonastronomical Adaptive Optics","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nonastronomical Adaptive Optics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1364/nao.1997.tua.4","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Uniform irradiation of laser beam is needed for the directly driven inertial confinement fusion, laser-chemistry and industrial applications such as laser welding, semiconductor processing and laser microfabrication. For improving the irradiation uniformity on a fusion target, several beam smoothing techniques such as a random phase plate (RPP)1, induced spatial incoherence (ISI)2, smoothing by spectral dispersion (SSD)3 and kinoform phase plate (KPP)4 have been proposed. The RPP has energy loss of ~ 15 % by a large diffraction angle, and the ISI and the SSD have imprint problems by instantaneous speckle pattern. The precise KPP with a continuous phase distribution is difficult to fabricate, even if the energy loss can be reduced to 5%. We are developing an active optical system to compensate (or control) a wavefront aberration included in a large-scale laser system for fusion. Shack-Hartmann wavefront sensor using a large F-number plastic micro-lens array5 and continuous faceplate type deformable mirror6 have been developed and their good performance has been demonstrated.