简介：Ramanspectroscopyisaversatiletoolwidelyusedforcomprehensiveprobingofcrystalinformation.However,generallywhenappliedinnarrow-band-gapvanderWaalscrystals,itisliabletoforma'bug,'especiallyintransition-metal-dichalcogenides(TMDs).Thatis,severalresonantRaman-scattering(RS)modeswillinevitablyappearintheRamanspectrawithstrongintensity,interferingwiththedesiredsignalofoptical-phononmodes.Here,weproposecross-sectionalpolarizedRamanscatteringcapableofregulatingtheintensityofRSmodesinaccordancewithquasi-sinusoidalrules.Typically,forMoS2andWS2,whenthepolarizationvectorofexcitedlightisalongthecaxisofthecrystal,allRSmodesarenearlycompletely'expunged'fromtheRamanspectra.ThemechanismisthattheabsorptionofmostTMDswithaspacegroupofR3mforthelightpolarizedalongthecaxisisinfinitesimal,thusformingasmallcouplingintensityofelectronicstatesexcitedopticallyandacoustic-phononmodesatpointM,whichinturnrestraintheappearanceofRSmodes.TheregulatingstrategyproposedcanbeappliedtoothervanderWaalscrystalssoastoobtainahighsignal-to-noiseratioRamanspectrum.

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