Fig. 1: CV molecules on Au nanohelices constitute a doubly resonant system for hyper-Raman scattering.
From: Chirality conferral enables the observation of hyper-Raman optical activity
a, Schematic diagram of the reported hyper-Raman optical activity effect: illumination with LCP and RCP results in different intensities of hyper-Raman scattering. b, The nanohelices have strong resonances at 1,064 nm and not at 532 nm, as demonstrated by simulations of the Rayleigh scattering cross-section spectra. c, The crystal violet (CV) molecules have strong resonances at 532 nm and not at 1,064 nm, as shown by their absorbance spectra. d, Surface-enhanced Raman scattering (SERS) (top) and surface-enhanced hyper-Raman scattering (SEHRS) (bottom) circular intensity sum (CIS) spectra of CV. e, Scanning electron microscopy (SEM) and scanning electron transmission microscopy (STEM) images of Au nanohelices. Left: SEM images present left- and right-handed nanohelix arrays on Si wafer. Middle: STEM images present a single nanohelix isolated and deposited on a STEM grid. Right: SEM images present top-down views of left-handed (left) and right-handed (right) Au nanohelices.
