超快激光超短激光脉冲测量理论方案.ppt

Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,光电子技术精品课程,大标题,飞秒脉冲的测量方案,(Measurement of an,ultrashort,pulse),Outlines,为什么测量超短脉冲是一项挑战,?,为什么要对超短脉冲进行测量,?,对超短脉冲的全面描述需要那些测量量？,光谱仪与,Michelson,干涉仪,自相关法,频率分辨光学开关法,(FROG),光谱相位干涉直接电场重构法,(SPIDER),超短脉冲的测量,：自相关法,Outlines,Intensity Autocorrelation,Single-shot autocorrelation,Third-order Autocorrelation,Intensity Cross-Correlation,Interferometric Autocorrelation,强度自相关器,Crossing beams in an SHG crystal,varying the delay between them,and measuring the second-harmonic(SH)pulse energy vs.delay,yields the,Intensity Autocorrelation,:,The Intensity Autocorrelation:,Delay,Beam-splitter,Input,pulse,Aperture eliminates input pulses,and also any SH created by,the individual input beams.,Slow,detector,Mirror,E(t),E(t,t,),Mirrors,SHG,crystal,Lens,What if we use a,collinear beam geometry,and allow the autocorrelator,signal light to interfere with the SHG from each individual beam?,Developed by J-C Diels,Usual,Autocor-,relation,term,New,terms,Also called the“Fringe-Resolved Autocorrelation”,Filter,Slow,detector,SHG,crystal,Lens,Beam-,splitter,Input,pulse,Delay,Mirror,Mirror,E(t),E(t,t,),Michelson Interferometer,Diels and Rudolph,Ultrashort Laser Pulse Phenomena,Academic Press,1996.,干涉自相关器,Outlines:,The Musical Score and the Spectrogram,Frequency-Resolved Optical Gating(,FROG,),SHG-FROG and other geometries,XFROG,Single-shot FROG and GRENOILLE,超短脉冲测量,：频率分辨光开关法,FROG,：,用复制的可延迟的脉冲与原脉冲在非线性介质中的瞬时相互作用作为,光学开关,；对开关脉冲随时间的变化进行,光谱分辨,。,Use any ultrafast nonlinearity:,Second-harmonic generation,etc.,“,Polarization Gate”Geometry,Nonlinear,medium(glass),Pulse to be measured,Variable delay,t,Camera,Spec-,trometer,Beam,splitter,E,(,t,),E,(,t-,t,),E,sig,(,t,t,),=E,(,t,),|E,(,t-,t,)|,2,45 polarization rotation,频率分辨光学开关法,(FROG),Baltuska,Pshenichnikov,and Weirsma,J.Quant.Electron.,35,459(1999).,SHG FROG Measurements of a 4.5-fs Pulse!,超短脉冲测量,：,SPIDER,What is SPIDER?,How SPIDER works?,SPIDER apparatus,X-SPIDER,Outlines:,t,Chirped pulse,t,t,t,This pulse sums with the blue part of the chirped pulse.,This pulse sums with the green part of the chirped pulse.,Two replicas of the pulse are produced,each frequency shifted by a different amount.,Performing SI on these two pulses yields the difference in spectral phase at nearby frequencies(separated by,dw,).This yields the spectral phase.,Input pulses,Output pulses,Iaconis and Walmsley,JQE 35,501(1999).,SFG,How SPIDER works,广州固润光电,Spectrometer,SHG,crystal,Filter,Focusing,Lens,Lens,Delay,Line,Delay,Line,Grating,Grating,BS,BS,M,BS,BS,Michelson,Interferometer,Pulse Stretcher,Input,Aperture,SPIDER apparatus,By guruntech,