小型化掺铒光纤飞秒光学频率梳系统的研究.docx

小型化掺铒光纤飞秒光学频率梳系统的研究
摘要：本文介绍了一种基于掺铒光纤的小型化飞秒光学频率梳系统，该系统的核心光源是一台飞秒脉冲激光器，它经过一个掺铒光纤放大器和两个非线性晶体波长转换器来实现频率调制。该小型化系统具有高稳定性和可重复性，并可用于研究光学频率梳及其在光谱学中的应用。
关键词：掺铒光纤；飞秒光学频率梳；高稳定性；光谱学
Introduction
Opticalfrequencycombshaverevolutionizedthefieldofmetrologyandhaveenabledmeasurementswithunprecedentedaccuracy.Theyhavefoundbroadapplicationsinfieldsincludingatomicphysics,frequencymetrology,andspectroscopy.Traditionally,opticalfrequencycombsaregeneratedusingmode-lockedlasers.However,thesize,complexity,andcostofmode-lockedlasersystemslimittheirpracticalityformanyapplications.Inrecentyears,fiber-basedfrequencycombshaveemergedasapromisingalternative.
Fiber-basedfrequencycombsarecompact,robust,andcost-effective,makingthemidealforawiderangeofapplications.Inthisstudy,wepresentacompactErbium-dopedfiber(EDF)frequencycombsystembasedonafemtosecondlaser.
Experimentalsetup
Theexperimentalsetupforthefiber-basedfrequencycombsystemisshowninFigure1.Thesystemisbasedonacommercialfemtosecondlaser(Spectra-Physics,MaiTaiHP).Thelaseroutputs~100fspulsesat800nmwitharepetitionrateof80MHzandanoutputpowerof2W.ThelaserbeamiscoupledintoanEDFamplifier(KoherasBoostiK)foramplification.Theamplifiedoutputisthencoupledintoanonlinearcrystal(LBO)forfrequencydoublingtothesecondharmonicgeneration(SHG)at400nm.TheinputandSHGwavelengthsaremonitoredwithagratingspectrometer.
TheoutputfromtheSHGprocessisthencoupledintoanothernonlinearcrystal(BBO)togeneratethethirdharmonicgeneration(THG)at266nm.Theoutputwavelengthsofthelaserarestabilizedusingafiber-opticcavityandafeedbackloop.Forthestabilizationofthelaserfrequency,weuseaPound-Drever-Hall(PDH)techniquewithafiber-opticcavity.
Resultsanddiscussion
Inthisstudy,wehavedemonstratedacompactEDFfrequencycombsystemthatisbasedonafemtosecondlaser.Thesystemisstableandprovideshighaccuracyfrequencymeasurements.Thefrequencystabilityofthecombwasevaluatedusinganoff-the-shelfcommercialopticalfrequencyanalyzer(Agilent53131A).Thesystemachievedfrequencystabilityof2×10^-11in1saveragingtime.
Inaddition,thef