SYSTEM AND METHOD FOR HIGH SENSITIVITY VIBRATIONAL IMAGING WITH FREQUENCY MODULATION COHERENT ANTI-STOKES RAMAN SCATTERING ANALYSES

摘要

A system is disclosed for detecting a nonlinear coherent field induced in a sample. The system includes optics, a modulation system, and a detector system. The optics are for directing a first electromagnetic field at a first frequency Ωi and a second electromagnetic field at a second frequency Ω2 toward a focal volume such that a difference frequency Ω1-Ω2 is resonant with a vibrational frequency of a sample in the focal volume. The modulation system is for modulating the difference frequency Ωi-Ω2 such that the difference frequency ΩrΩ2 is tuned in and out of the vibrational frequency of the sample at a modulation frequency. The detector system is for detecting an optical field that is generated through non-linear interaction of Ω1 and Ω2 and the sample responsive to the modulation frequency. The system is in particular intended for use in coherent Anti-Stokes Raman Spectroscopy (CARS).