Experimental demonstration of nanoCARS: coherent anti‐Stokes Raman scattering in mesoporous silica aerogels infiltrated with condensed‐ and gas‐phase Raman‐active materials

Abstract

Coherent anti-Stokes Raman scattering (CARS) is shown to allow the reliable detection of Raman-active modes of gas-phase molecular nitrogen, and also toluene molecules in the condensed and gas phases infiltrated into mesoporous silica aerogels. We experimentally demonstrate a nanoscale extension of CARS methodology, referred to as nanoCARS, adapting CARS for local probing of nanostructures and nanocomposite materials, and also for the sensing of Raman-active species in the liquid and gas phases in a nanocomposite host.

Advances in nonlinear optical spectroscopies: a historical perspective of developments and applications presented at ECONOS

“…This suggested a change in the ratio of the signal contributions from toluene molecules and the porous glass host. The same group demonstrated a nanoCARS approach to study gaseous nitrogen as well as toluene in the gas‐ and liquid‐phase inside mesoporous silica aerogels . The theoretical principles of the nanoCARS technique, which must not be mixed up with microscopic versions of CARS, were summarized by Zheltikov .…”

“…In contrast to CARS microscopy, which is intended to resolve individual micro‐objects, the interferometric nanoCARS technique is not capable of resolving individual nanocrystals in a nanocomposite material. However, it can locally probe the effective‐medium linear and nonlinear optical properties of a nanostructure …”

“…The same group demonstrated a nanoCARS approach to study gaseous nitrogen as well as toluene in the gas-and liquid-phase inside mesoporous silica aerogels. [156] The theoretical principles of the nanoCARS technique, which must not be mixed up with microscopic versions of CARS, were summarized by Zheltikov. [157] In contrast to CARS microscopy, which is intended to resolve individual micro-objects, the interferometric nanoCARS technique is not capable of resolving individual nanocrystals in a nanocomposite material.…”

“…However, it can locally probe the effective-medium linear and nonlinear optical properties of a nanostructure. [156]…”

Non‐linear Raman spectroscopy 75 years after the Nobel Prize for the discovery of Raman scattering and 40 years after the first CARS experiments

“…In particular, De Dominicis et al 23 present an interesting analysis of the chiral composition of carbon nanotubes by means of second harmonic generation. The possibility of using CARS spectral profiles for local probing of nano-and mesoporous materials and aerogels was demonstrated both experimentally and theoretically by Konorov et al 24 and Zheltikov. 25 We would like to use this opportunity to thank cordially Dr Thomas Seeger and his team at the University of Erlangen for the excellent job they did and the superb organization of the ECONOS meeting.…”