Single-pulse phase-control interferometric coherent anti-Stokes Raman scattering spectroscopy

In coherent anti-Stokes Raman scattering (CARS) spectroscopy experiments, usually the amplitude of the signal is measured and the phase information is lost. With a polarization- and phase-controlled pulse shaping technique, the relative phase between the resonant and nonresonant CARS signals is controlled, and spectral interferometry is performed without an interferometer. Both the real and imaginary parts of the background-free resonant CARS spectrum are measured via spectral interferometry between the resonant and nonresonant signals from the same sample. The resonant signal is amplified significantly by homodyne mixing with the nonresonant signal as a local oscillator, greatly improving the detection limit.