简介：Diffractiveopticsisanimportanttechniqueforbeamshapingwithhighlightefficiencyandstrongdiffractionpatternflexibility.Sincethediffractionangleislimitedbytheunitsizeofthediffractiveopticalelement(DOE),thesizeoftherequireddiffractionpatternisalwaysrathersmall.InthisLetter,refractive/diffractivehybridopticalelements(RDHOEs)consistingofaDOEandalensareusedtorealizebeamshapingforalargediffractionpattern.Thelens,asthecomponentoftheRDHOEs,cannotonlybeconcavebutalsoconvex,andthedoublesamplingFresneldiffractionalgorithmisdevelopedforthedesignofthesetwotypesofRDHOEs.Thesimulationandexperimentalresultsprovidesolidevidencetodemonstratetheproposedmethodwiththepurephasespatiallightmodulator.

简介：当microsatellite技术发展，精确内部卫星的测量在分布式的卫星系统显示出它的意义。在这封信，一种新奇技术为测量内部卫星的距离被建议，它采用optoelectronic回声并且有功能自我引用。回声洞有高度光谱纯净和高摆动频率。由利用积聚的扩大原则把距离的测量变换成频率的，高精确性被完成。在实验，这个测量计划有在1和6km之间的一个大测量范围(能潜在地更大)，并且精确性比1.5m好。相对精确性到达1010的水平。

简介：Wereportontheamplificationofhigh-average-powerandhigh-efficiencypicosecondpulsesinaself-madeverylarge-mode-areaYb-dopedphotoniccrystalfiber(PCF).ThePCFwithacorediameterof105μmandacorenumericalapertureof0.05ispreparedbythesol-gelmethodcombinedwiththepowdersinteringtechnique.Thefiberamplificationsystemproducesthehighestaveragepowerof255Wata10MHzrepetitionratewitha21pspulsedurationcorrespondingtoapeakpowerof1.2MW.Thisresultexemplifiesthehigh-average-powerandhigh-peak-powerpotentialofthisspecificallydesignedfiber.