All‐dielectric core/shell resonators: From plasmon‐free SERS to multimodal analysis

Abstract

All‐dielectric materials are emerging as a new class of substrates for enhanced Raman scattering. As ohmic losses are reduced in the absence of plasmonic metals, Raman data obtained with dielectrics are very reproducible and reliable. This mini‐review summarizes our recent work in the field of core/shell dielectric resonators designed for Raman purposes, with a special focus on SiO2/TiO2 (T‐rex) core/shell beads. These systems are able to exploit the evanescent field generated by total internal reflection and multiple scattering of light at the sphere‐to‐sphere interface to multiply the number of Raman photons, improving the sensitivity of Raman detection and extending the application of surface enhanced Raman scattering for investigating surface chemical reactions. Examples of the application of T‐Rex beads in detecting and monitoring environmental pollutants, greenhouse gases, biochemical species, and biochemical reactions are presented. The use of core/shell resonators for multimodal analysis based on the combination of surface enhanced Raman scattering with either mass spectrometry or refractive index optical sensing is also discussed, suggesting different possible future developments.

Editorial: Surface Enhanced Raman Scattering: New Theoretical Approaches, Materials and Strategies

“…In recent years, significant progress has been reported that promises to bring SERS to the forefront of sensing and advanced diagnostics. Several research groups demonstrated that dielectrics can be suitably engineered to achieve non-plasmonic enhanced Raman scattering, reducing invasiveness and increasing reproducibility of SERS experiments (Alessandri, 2013;Alessandri and Lombardi, 2016;Bontempi et al, 2018).…”

Recent advances in linear and nonlinear Raman spectroscopy. Part XIII

“…Bontempi and co‐workers described all‐dielectric core/shell resonators from plasmon‐free SERS to multimodal analysis. They conclude that the use of core/shell resonators, based on the combination of SERS with either mass spectrometry or refractive index optical sensing, suggests different possible future developments . Chen and co‐workers used sonochemical and mechanical stirring for the synthesis of liquid metal nanograss structures as low‐cost SERS substrates.…”

“…The meeting also serves as the annual meeting of the Society of Applied Spectroscopy. This year, SCIX 2019 was held [13][14][15][16][17][18] October in Palm Springs, California. Highlights of particular sessions that featured Raman spectroscopy are the following: It can be seen from these session topics that SCIX highlights the use of Raman at the frontier of analytical applications for a wide variety fields and techniques.…”

“…They conclude that the use of core/shell resonators, based on the combination of SERS with either mass spectrometry or refractive index optical sensing, suggests different possible future developments. [15] Chen and co-workers used sonochemical and mechanical stirring for the synthesis of liquid metal nanograss structures as low-cost SERS substrates. The method is a facile, large scale, low cost, and green synthesis of a liquid metal nanograssstructured substrate with high SERS activity that makes it an ideal choice for practical SERS detection applications.…”

GISR 2017: Present and future of Raman researches in Italy

“…An interesting review concerning the all-dielectric materials as emerging new class of substrates for SERS was provided during the conference. [4] The core/shell dielectric resonators designed for Raman purposes have the capacity to exploit the evanescent field generated by total internal reflection and multiple scattering of light at the sphere-to-sphere interface thus leading to a significant improvement of the sensitivity of Raman detection. Examples of application of this SERS technology can be found in detecting and monitoring environmental pollutants, greenhouse gases, biochemical species, and biochemical reactions.…”