Cars microscope

A coherent anti-Stokes Raman scattering (CARS) microscope comprising:

• a pulsed laser light source configured to generate a first beam with a frequency ωP;
• a normal dispersion nonlinear optical fiber configured to receive the first beam and generate a supercontinuum beam;
• an optical element configured to select, from the supercontinuum beam, a second beam with a frequency ωST that is lower than the frequency of the first beam, and to select, from the supercontinuum beam, a third beam as a reference beam with a frequency ωAS=2ωP−ωST;
• a mechanism including one or more mirrors configured to adjust phases of the first beam and the second beam;
• an optical unit configured to align the first beam and the second beam on a same axis;
• an objective lens configured to focus the first beam and the second beam that are coaxial beams onto an observation sample;
• a stage configured to move to scan the observation sample with the coaxial beams;
• an interference optical unit configured to cause a CARS beam generated from the observation sample and the third beam to interfere with each other;
• a plurality of beam splitters that are each configured to decompose a respective interference beam obtained from the interference optical unit;
• a plurality of spectrometers each configured to detect a respective beam decomposed by one of the beam splitters;
• a computing unit configured to process signals from the spectrometers;
• and
• a display device configured to display an image based on the signals processed by the computing unit.