Fiber-format CARS spectroscopy by spectral compression of femtosecond pulses from a single laser oscillator

Opt Lett. 2009 Nov 1;34(21):3262-4. doi: 10.1364/OL.34.003262.

Abstract

We demonstrate an approach to coherent anti-Stokes Raman scattering (CARS) spectroscopy/microscopy based on spectral compression of femtosecond pulses emitted by a compact Er-fiber oscillator. Spectral compression is achieved by group-velocity mismatched second-harmonic generation in periodically poled nonlinear crystals, and it allows efficient synthesis of synchronized narrow-bandwidth (less than 10 cm(-1)) pump and Stokes pulses with the frequency difference continuously tunable up to approximately 3000 cm(-1). CARS signal enhancement by up to 3 orders of magnitude is obtained by interferometric superposition with a phase-coherent local oscillator field, also synthesized by spectral compression.

MeSH terms

  • Lasers*
  • Microscopy
  • Spectrum Analysis, Raman / methods*
  • Time Factors