Optical probe, Raman spectroscopy system, and method of using the same

A Raman spectroscopy system comprising:

• a spectrometer comprising a sensor;
• a light source;
• an optical probe comprising an excitation optics, a detection optics, a sampling optics, a first beam splitter, and a second beam splitter, wherein the excitation optics and the detection optics are optically coupled to the sampling optics via the first beam splitter and in confocal arrangement with a sample focal plane of the sampling optics, wherein the sampling optics and the detection optics are arranged to receive a Raman signal from the sample focal plane and direct it onto a tip of a detection optical fiber, the optical probe further comprising
• a bandpass filter arranged between the first beam splitter and the excitation optics, wherein the bandpass filter is configured to only allow an excitation light from the light source to pass through, and
• a notch filter arranged between the first beam splitter and the detection optics, wherein the notch filter is configured to block the excitation light from passing through into the detection optics, and
• wherein the first beam splitter is arranged to reflect the excitation light received directly from the bandpass filter to the sampling optics and to allow transmission of the Raman signal from the sampling optics to the detection optics;
• wherein the second beam splitter is configured to allow transmission of the excitation light and of the Raman signal and further configured to reflect light received from a sample which is illuminated directly with a broadband light source and which is at a wavelength different from the excitation light and from the Raman signal for imaging purpose,
• wherein the light source is configured to be optically coupled to a tip of an excitation optical fiber which is distal from the excitation optics;
• wherein the spectrometer is configured to be optically coupled to a tip of the detection optical fiber which is distal from the detection optics,
• wherein the excitation optics comprises a first collimator,
• wherein the detection optics comprises a second collimator, and
• wherein the first collimator is identical to the second collimator.

A method for measuring Raman signal depth profile in a sample, with a Raman spectroscopy system comprising:

• a spectrometer;
• an optical probe comprising an excitation optics, a detection optics, a sampling optics, a first beam splitter, and a second beam splitter, wherein the excitation optics and the detection optics are optically coupled to the sampling optics via the first beam splitter and in confocal arrangement with a sample focal plane of the sampling optics, wherein the sampling optics and the detection optics are arranged to receive a Raman signal from the sample focal plane and direct it onto a tip of a detection optical fiber, the optical probe further comprising
• a bandpass filter arranged between the first beam splitter and the excitation optics, wherein the bandpass filter is configured to only allow an excitation light from a light source to pass through, and
• a notch filter arranged between the first beam splitter and the detection optics, wherein the notch filter is configured to block the excitation light from passing through into the detection optics,
• wherein the excitation optics comprises a first collimator,
• wherein the detection optics comprises a second collimator, and
• wherein the first collimator is identical to the second collimator, and
• wherein the first beam splitter is arranged to reflect the excitation light received directly from the bandpass filter to the sampling optics and to allow transmission of the Raman signal from the sampling optics to the detection optics;
• wherein the second beam splitter is configured to allow transmission of the excitation light and of the Raman signal and further configured to reflect light received from a sample which is illuminated directly with a broadband light source and which is at a wavelength different from the excitation light and from the Raman signal for imaging purpose, and
• a positioning device mechanically coupled to the sampling optics and configured to control a position of the sample focal plane;
• the method comprising:
• (i) driving the positioning device thereby controlling the position of the sample focal plane to a first position;
• (ii) measuring the Raman signal;
• and
• (iii) recording at least one of the Raman signal or a processed information obtained from processing the Raman signal, at the first position and storing an associated data record containing an information in respect to the first position.