Stimulated raman nanospectroscopy

摘要

A method for achieving measurable sample heating in the vicinity of a probe microscope tip using Stimulated Raman Spectroscopy. Two laser sources, preferably in the UV visible or near IR illuminate the sample, preferably in overlapping diffraction limited spots. At least one of the sources is swept through a frequency range such that the difference frequency corresponds to IR spectral regions of interest. Selective Absorption by differing sample materials at the difference frequency causes measurable sample heating detectable by the probe tip related to IR spectral absorption bands. Thus very high spatial resolution IR spectroscopy may be achieved.

主权项

1. A method of operating a probe microscope to obtain a vibrational spectrum of a sub-micron region of sample using stimulated Raman excitation, the method comprising:
a. illuminating a sample with at least two beams of radiation wherein the two beams have a wavenumber difference of Δσ; b. interacting a tip of a probe microscope with a surface of the sample; c. measuring a probe response resulting from heating of the region of the sample due to absorption of energy at a wavenumber corresponding to Δσ; d. sweeping the wavenumber of at least one of the illuminating beams to measure the probe response as a function of wavenumber difference Δσ; e. Creating a vibrational spectrum of the region of the sample using the probe response as a function of wavenumber difference Δσ.