Abstract: An illumination system is disclosed for providing dual-excitation wavelength illumination for non-linear optical microscopy and micro-spectroscopy. The illumination system includes a laser system, an optical splitting means, a frequency shifting system, and a picosecond amplifier system. The laser system includes a laser for providing a first train of pulses at a center optical frequency ?1. The optical splitting means divides the first train of pulses at the center optical frequency ?1 into two trains of pulses. The frequency shifting system shifts the optical frequency of one of the two trains of pulses to provide a frequency shifted train of pulses. The picosecond amplifier system amplifies the frequency shifted train of pulses to provide an amplified frequency-shifted train of pulses having a pulse duration of at least 0.5 picoseconds.

Abstract: Systems and methods are disclosed for detecting a coherent anti-Stokes Raman scattering (CARS) signal from a microscopic sample in an epi-direction. In an embodiment, the system includes at least two sources having a pump source for generating a pump field at the pump frequency, a Stoke source for generating a Stoke field at the Stoke frequency that is different from the pump frequency, optics (64) for directing the pump and Stoke beams (60) in a collinear fashion through a focusing lens (66) toward a common focal spot in a sample (70), and detector optics that images the CARS in epi-direction, which is generated by the interaction of the pump and Stoke fields (60) with the sample (70) and is collected by the same focusing lens (66), towards an epi-detector (78).

Abstract: Systems and methods are disclosed for detecting a nonlinear coherent field induced in a microscopic sample. The system includes in an embodiment, a first source for generating a first polarized electromagnetic field at a first frequency and a second source for generating a second polarized electromagnetic field at a second frequency that is different from the first frequency. The system further includes optics for combining the first polarized electromagnetic field and the second polarized electromagnetic field in a collinear fashion such that the difference in polarization angles is &phgr; wherein &phgr; is not equal to zero. The optics further direct the combined electromagnetic field toward a common focal volume. The system also includes a polarization sensitive detector for detecting a nonlinear coherent field that is generated responsive to the first and second polarized electromagnetic fields in the focal volume.