Stimulated Raman photothermal microscope with optical parametric amplifier source

A stimulated Raman photothermal (SRP) microscope for imaging a sample, comprising:

• a first optical source emitting a pump beam and lacking an optical resonator;
• a second optical source emitting a Stokes beam, wherein the Stokes beam is combined with the pump beam to form a combined beam, the combined beam being directed to the sample to induce a thermal effect caused by the stimulated Raman process;
• a third optical source emitting a probe beam, wherein the probe beam is directed to the sample;
• one or more optical detectors configured to detect modulation of the probe beam after modulation by the sample to measure an SRP signal;
• and
• at least one lens positioned within an optical path of the combined beam and probe beam,
• wherein the probe beam is directed to the sample colinear with the combined beam and the at least one lens adjusts the collimation of the probe beam to make the probe beam focus axially off a focus of the combined beam.

A stimulated Raman photothermal (SRP) microscope for imaging a sample, comprising:

• a first optical source emitting a pump beam and lacking an optical resonator;
• a second optical source emitting a Stokes beam, wherein the Stokes beam is combined with the pump beam to form a combined beam, the combined beam being directed to the sample to induce a thermal effect caused by the stimulated Raman process;
• a third optical source emitting a probe beam, wherein the probe beam is directed to the sample;
• one or more optical detectors configured to detect modulation of the probe beam after modulation by the sample to measure an SRP signal,
• wherein the measured SRP signal is based on the local refractive index modulation of the sample, determined from the detected probe beam.