title: Fiber-format CARS spectroscopy by spectral compression of femtosecond pulses from a single laser oscillator.
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.
authors.affiliation: Dipartimento di Fisica, Politecnico di Milano, ULTRAS-CNR-INFM, IFN-CNR Piazza Leonardo da Vinci 32, 20133 Milano, Italy. marco.marangoni@polimi.it
authors.forename: Marco
authors.initials: M
authors.lastname: Marangoni
authors.forename: Alessio
authors.initials: A
authors.lastname: Gambetta
authors.forename: Cristian
authors.initials: C
authors.lastname: Manzoni
authors.forename: Vikas
authors.initials: V
authors.lastname: Kumar
authors.forename: Roberta
authors.initials: R
authors.lastname: Ramponi
authors.forename: Giulio
authors.initials: G
authors.lastname: Cerullo
mesh_terms: D007834:Lasers; D008853:Microscopy; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013997:Time Factors