title: Fiber laser-based light source for coherent anti-Stokes Raman scattering microspectroscopy.
abstract: We demonstrate an alternative light source for CARS microspectroscopy based on a fiber laser and a photonic-crystal fiber. The light source simultaneously delivers a near-transform-limited picosecond pump pulse at 1033.5 nm and a frequency-shifted, near-transform-limited femtosecond Stokes pulse, tunable from 1033.5 nm to 1400 nm. This corresponds to a range 0 - 2500 cm(-1), so that Raman-active vibrations in this frequency range can be probed. The spectral resolution is 5 cm(-1), given by the spectral width of the pump pulse. The frequency range that can be probed simultaneously is 200 cm(-1)-wide, given by the spectral width of the Stokes pulse. The achievable pulse powers are 50 mW for the pump and 2 mW for the Stokes pulse. The repetition rate is 35 MHz. We demonstrate the capability of this light source by performing CARS microspectroscopy and comparing CARS spectra with Raman spectra.
authors.affiliation: Department of Physics and Astronomy, University of Aarhus, Ny Munkegade, DK-8000 Aarhus C, Denmark. esbenra@phys.au.dk
authors.forename: Esben R
authors.initials: ER
authors.lastname: Andresen
authors.forename: Carsten K
authors.initials: CK
authors.lastname: Nielsen
authors.forename: Jan
authors.initials: J
authors.lastname: Thøgersen
authors.forename: Søren R
authors.initials: SR
authors.lastname: Keiding