Fiber laser-based light source for coherent anti-Stokes Raman scattering microspectroscopy

• Published in: Optics express Vol. 15; no. 8; pp. 4848 - 4856
• Main Authors: Andresen, Esben R, Nielsen, Carsten K, Thøgersen, Jan, Keiding, Søren R
• Format: Journal Article
• Language: English
• Published: United States 16-04-2007
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/oe.15.004848

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.