Background-free coherent anti-stokes Raman spectroscopy by all-fiber-generated dual-soliton as Stokes pulse

We propose an all-fiber based scheme for the background-free detection of coherent anti-Stokes Raman spectroscopy using dual-soliton as Stokes pulses under the spectral focusing mechanism. Efficient suppression of the nonresonant background can be directly achieved exploiting the difference of the two soliton pulse in both time and frequency domain relying on pulse breakup and soliton self-frequency shifts in a polarization-maintaining photonic crystal fiber.