Patent ID: 11860106
Assignee: SANGUIS CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 20:
21. A system for high gain stimulated Raman spectroscopy comprising:
a first continuous wave laser having a first output beam at a tunable optical frequency which is modulated at a first RF modulation frequency (f1) and a first average power of laser radiation;
a second continuous wave laser having a second output beam at an optical frequency which is modulated at a second RF modulation frequency (f2) and a second average power of laser radiation which is modified by pulsing the output beam, wherein the first and second RF modulation frequencies (f1, f2) are selected such that their difference or sum beat notes (f1−f2; f1+f2) represent a Raman resonance frequency;
a beam spreader that expands the first and second output beams into first and second expanded beams having reduced average power per unit area in comparison to the first and second output beams;
first and second photosensors optically coupled to the first and second continuous wave lasers and the beam spreader;
wherein the first and second expanded beams are directed onto a sample over an exposure area, and in response thereto is stimulated by the laser beams to emit Raman radiation signals which are directed to the first and second photosensors, the first and second photosensors having respective first and second outputs responsive to the first and second expanded beams and the Raman signals emitted from the sample; and
a differential amplifier coupled to outputs of the first and second photosensors of the R-probe that is configured to provide sensitivity and gain to signals at the beat note resonant frequency (f1−f2) and to filter out signals at other frequencies so as to output the Raman radiation signals with gain.