Dresden 2011 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 15: Linear and nonlinear Raman Spectroscopy

MO 15.5: Vortrag

Mittwoch, 16. März 2011, 15:45–16:00, MER 02

Picosecond supercontinuum-based hyperspectral CARS imaging — •S. Gomes da Costa, G. Hehl, and A. Volkmer — 3. Physikalisches Institut, Universität Stuttgart, 70569 Stuttgart

Hyperspectral coherent anti-Stokes Raman scattering (CARS) imaging has been demonstrated to provide both spatially and frequency resolved vibrational spectroscopy with sub-micron and 5-cm-1 resolutions, respectively, within complex heterogeneous samples. In previous realizations of multiplex CARS microspectroscopy, narrowband pump- and probe pulses and a broadband femtosecond or supercontinuum (SC)-based Stokes pulse have been used in CARS process. The SC is conventionally generated in a highly nonlinear photonic crystal fibre (PCF) using a femtosecond seed pulse. As a consequence, the Stokes-continuum and the narrowband pump pulses are temporally mismatched, resulting in inefficient CARS-continuum generation. To optimize CARS, matching the temporal widths of both the pump and Stokes-continuum pulses and the spectral widths of the picosecond pump pulse and the vibrational bandwidth of interest are required. Here, we report on the first experimental realization of vibrational bandwidth-matched picosecond supercontinuum-based hyperspectral CARS imaging using a single Ti:sapphire laser oscillator with 3-ps near-transform-limited pulses. In addition to XFROG-CARS measurements, we demonstrate the increased CARS detection sensitivity, the spatial, and the spectral resolutions of our novel setup by performing three-dimensional hyperspectral CARS imaging on well-defined test samples.