@article {1803, title = {Background-free coherent anti-stokes Raman scattering of gas- and liquid-phase samples in a mesoporous silica aerogel host}, journal = {Applied Spectroscopy}, volume = {61}, number = {5}, year = {2007}, note = {Konorov, Stanislav O. Turner, Robin F. B. Blades, Michael W.}, month = {May}, pages = {486-489}, abstract = {Efficient time-resolved coherent anti-Stokes Raman scattering (CARS) of atmospheric nitrogen and ethanol trapped in a nanoporous silica aerogel matrix is demonstrated. Silica aerogel hosts are attractive for analytical CARS spectroscopy due to their high porosity/low density, low refractive index, and low scattering cross-section. Differences between the resonant and nonresonant parts of the nonlinear optical susceptibilities lead to much longer relaxation times for analytes compared to the matrix. Time-resolved CARS can then be used to obtain a nearly background-free measurement at characteristic vibrations of the analyte. These results demonstrate the potential of this approach for rapid, sensitive, background-free analyses of analytes entrapped in the aerogel pores, which may be advantageous for some environmental, chemical, and biological sensing applications.}, isbn = {0003-7028}, url = {://000246433600005}, author = {Konorov, S. O. and Turner, R. F. B. and Blades, M. W.} }