High-sensitivity vibrational imaging with frequency modulation coherent anti-Stokes Raman scattering (FM CARS) microscopy.
We demonstrate a new approach to coherent anti-Stokes Raman scattering (CARS) microscopy that significantly increases the detection sensitivity. CARS signals are generated by collinearly overlapped, tightly focused, and raster scanned pump and Stokes laser beams, whose difference frequency is rapidly modulated. The resulting amplitude modulation of the CARS signal is detected through a lock-in amplifier. This scheme efficiently suppresses the nonresonant background and allows for the detection of far fewer vibrational oscillators than possible through existing CARS microscopy methods.
Ganikhanov
Feruz
F
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.
Evans
Conor L
CL
Saar
Brian G
BG
Xie
X Sunney
XS
D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007834:Lasers; D008027:Light; D008853:Microscopy / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D013059:Spectrum Analysis, Raman / Q000379:methods*; D041623:Tomography, Optical Coherence / Q000379:methods*; D014732:Vibration