arXiv subjects

R. C. Maher

Publications and source records attributed to R. C. Maher.

3 recordsLinked to original sources

arXiv2006

On the Experimental Estimation of Surface Enhanced Raman Scattering (SERS) Cross Sections by Vibrational Pumping

We present an in-depth analysis of the experimental estimation of cross sections in Surface Enhanced Raman Scattering (SERS) by vibrational pumping. The paper highlights the advantages and disadvantages of the technique, pinpoints the main aspects and limitations, and provides the underlying physical concepts to interpret the experimental results. Examples for several commonly used SERS probes are given, and a discussion on future possible developments is also presented.

physics.chem-ph↗

arXiv2005

A conclusive demonstration of vibrational pumping and determination of SERS cross sections

We provide conclusive demonstration of vibrational pumping under Surface Enhanced Raman Scattering (SERS) conditions by performing anti-Stokes/Stokes ratio measurements down to 10 K using dried silver colloids, the dye rhodamine 6G and 676 nm laser excitation. The method we propose allows the measurement of the SERS cross sections for different modes and the determination of the asymmetry between the anti-Stokes and Stokes SERS cross sections.

physics.chem-ph↗

arXiv2005

Temperature dependent anti-Stokes/Stokes ratios under Surface Enhanced Raman Scattering (SERS) conditions

We make systematic measurements of Raman anti-Stokes/Stokes (aS/S) ratios using two different laser excitations (514 and 633 nm) of rhodamine 6G (RH6G) on dried Ag colloids over a wide range of temperatures (100 to 350 K). We show that a temperature scan allows the separation of the contributions to the aS/S ratios from {\it resonance effects} and {\it heating/pumping}, thus decoupling the two main aspects of the problem. The temperature rise is found to be larger when employing the 633 nm laser. In addition, we find evidence for mode specific vibrational pumping at higher laser power densities. We analyze our results in the framework of ongoing discussion on laser heating/pumping under SERS conditions.

physics.chem-ph↗