Microscopy imaging system and method employing stimulated raman spectroscopy as a contrast mechanism

A microscopy imaging system comprising:

• a first light source for providing a first train of pulses at a first center optical frequency ω1;
• a second light source for providing a second train of pulses at a second center optical frequency ω2 such that a difference between ω1 and ω2 is resonant with a vibrational frequency of a sample in the focal volume, wherein the second train of pulses is synchronized with the first train of pulses;
• a modulator system for modulating a property of the second train of pulses at a modulation frequency f of at least 100 kHz;
• focusing optics for directing and focusing the first train of pulses and the second train of pulses toward a common focal volume;
• an optical detector for detecting an integrated intensity of substantially all optical frequency components of the first train of pulses transmitted or reflected through the common focal volume by blocking the second train of pulses;
• and
• a processor for detecting a modulation at the modulation frequency f, of the integrated intensity of substantially all of the optical frequency components of the first train of pulses due to the non-linear interaction of the first train of pulses with the second train of pulses in the common focal volume, to provide a pixel of an image for the microscopy imaging system.