Abstract: In one embodiment, a system includes a pump light source configured to produce a pump beam of light at a pump frequency and a Stokes light source configured to produce a Stokes beam of light at a Stokes frequency. The pump and Stokes frequencies are offset by a frequency offset ?, and the pump and Stokes beams are directed to an object. The system further includes one or more optical elements configured to collect a Raman signal produced by coherent Raman scattering of the pump and Stokes beams of light at the object. The system also includes an optical receiver configured to detect the Raman signal. The optical receiver includes a probe light source configured to produce a probe beam of light at a probe frequency and an optical detector configured to coherently mix the Raman signal with the probe beam of light to produce a corresponding photocurrent signal.

Abstract: In one embodiment, a system includes a first light source configured to produce a first beam of light at a first frequency and a second light source configured to produce a second beam of light at a second frequency, where the first and second frequencies are offset by a frequency offset ?. The system also includes one or more optical elements configured to: direct the first and second beams of light to a sample, and collect a Raman signal produced by the sample in response to the first and second beams of light. The system further includes an optical receiver configured to detect the Raman signal. The optical receiver includes a third light source configured to produce a third beam of light at a third frequency, where the third light source includes a wavelength-tunable laser, where the third frequency is adjustable.