Comparison of the Sensitivity and Image Contrast in Spontaneous Raman and Coherent Stokes Raman Scattering Microscopy of Geometry Controlled Samples
Hyun M. Kim, Chris A. Michaels, Garnett W. Bryant, Stephan J. Stranick
We experimentally compare the performance and contrast differences between spontaneous and coherent Stokes Raman scattering microscopy. We demonstrate the differences on a series of geometry controlled samples that range in complexity from a point (array of tips) to one-dimensional (line grating) and lastly two-dimensional (checkered board) microstructure. Through the use of this sample series, a comparison of the focal volume, achievable signal-to-noise, and resulting image contrast is made. The results clearly demonstrate the improvement in efficiency and resolution afforded by coherent Raman microscopy. Additionally, we detail potential complications in coherent Raman image interpretation of sample fine structure where contrast is no longer based solely on oscillator concentration but can be influenced by geometric factors.