We demonstrate a significant improvement in signal-to-noise ratio in coherent anti-Stokes Raman scattering (CARS) spectroscopy/microscopy, using two highly synchronized picosecond Ti:sapphire lasers. A temporal jitter between the pulse trains from the two independent commercial lasers is reduced from a few picoseconds to ~21 fs , maintained over several hours. The tight synchronization brings the fluctuation of the CARS signal down to the shot-noise limit, leading to enhanced CARS vibrational images of living cells and polymer beads.
© 2002 Optical Society of America
(110.3080) Imaging systems : Infrared imaging
(140.7090) Lasers and laser optics : Ultrafast lasers
(300.6230) Spectroscopy : Spectroscopy, coherent anti-Stokes Raman scattering
(320.0320) Ultrafast optics : Ultrafast optics
Eric O. Potma, David J. Jones, J.-X. Cheng, X. S. Xie, and Jun Ye, "High-sensitivity coherent anti-Stokes Raman scattering microscopy with two tightly synchronized picosecond lasers," Opt. Lett. 27, 1168-1170 (2002)