简介：Higher-bandself-trappingandoscillation(rotation)ofnonlinearquadruplebeamsintwo-dimensional(2D)squarephotoniclatticesarenumericallydemonstrated.Underappropriateconditionsofnonlinearity,aquadruple-likebeamcanself-trapintolocalizedmodesthatresideinthesecondBraggreflectiongapthroughsingle-siteexcitation.Bychangingtheinitialorientationoftheincidentquadruplebeamrelatedtothelattices,periodicoscillationsofthelocalizedquadruplemodemaybeobtained.Thelocalizedquadruplestatebecomesarotatingdoublychargedopticalvortex(DCV)duringrotationandshouldundergocharge-flippingwhentherotatingdirectionisreversed.

简介：Wereportaline-narrowedelectro-opticperiodically-poled-lithium-niobate(PPLN)Q-switchedlaserwithintra-cavityopticalparametricoscillationusingagrazing-incidencegrating,producing8-ns,5-μJpulsesat10-kHzrepetitionratewhenpumpedwitha10-Wdiodelaserat808nm.Theoutputwavelengthiscenteredat1554.3nmwitha0.03-nmspectralwidth.Wavelengthtuningisachievedbyrotatingamirrorandchangingthecrystaltemperature.