Stimulated Raman scattering using a single femtosecond oscillator with flexibility for imaging and spectral applications

Stimulated Raman scattering (SRS) is a powerful tool for obtaining background-free chemical information about a material without extrinsic labeling. Background-free spectra are particularly important in the fingerprint region (similar to 800 and 1800 cm(-1)) where peaks are narrow, closely-spaced, and may be in abundance for a particular chemical. We demonstrate a method for obtaining SRS spectra using a single femtosecond laser oscillator. A photonic crystal fiber is used to create a supercontinuum to provide a range of Stokes shifts from similar to 300 to 3400 cm(-1). This SRS approach provides for collection capabilities that are easily modified between obtaining broadband spectra and single-frequency images. (C) 2011 Optical Society of America