Enhanced Raman Scattering for Probing Near‐Field Distribution in All‐Dielectric Nanostructures

Abstract

Resonant all‐dielectric nanophotonic structures have recently demonstrated enhancement of light emission and localization of near‐fields outside and inside the nanoresonators of various functionality. However, probing of the near‐field is still a time‐consuming and challenging procedure, requiring near‐field optical microscopy or cathodoluminescence approaches. On the contrary, inherent light emission such as Raman scattering from all‐dielectric nanostructures can provide important information on their resonant properties. Herein, probing of near‐field spatial distribution around a silicon trimer qualitatively using far‐field excitation of Raman scattering is demonstrated. The geometry of a single excitation and collection objective with lateral scanning is implemented. With this technique, switching near‐field distribution in the silicon trimer by changing the polarization of the incident light is observed. The full‐wave numerical simulations support the observed experimental results. It is believed that such an approach will be useful for near‐field probing of various all‐dielectric resonant nanostructures with a simple far‐field optical scheme.

Keywords

• nanophotonics
• near-field distribution
• optical resonances
• Raman scattering
• silicon