Raman probes based on optically-poled double-clad fiber and coupler

Area of Science:

• Optics and Photonics
• Spectroscopy
• Materials Science

Background:

• Raman spectroscopy is a powerful technique for molecular analysis.
• Traditional fiber-based Raman probes face challenges with signal generation and background noise.
• Optically-poled fibers offer a novel approach for enhanced light generation within waveguides.

Purpose of the Study:

• To develop and present two distinct fiber Raman probe designs.
• To demonstrate the capability of optically-poled fibers for generating visible light for spectroscopy.
• To evaluate methods for efficient Raman signal collection and background reduction.

Main Methods:

• Fabrication of fiber Raman probes using optically-poled double-clad fibers.
• Illumination of the fiber core with 1064nm laser light to generate 532nm light via optical poling.
• Raman spectroscopy of dimethyl sulfoxide (DMSO) samples.
• Signal collection in the inner cladding and retrieval using a bulk dichroic mirror or a double-clad fiber coupler.

Main Results:

• Successful generation of 532nm light within the optically-poled fiber core.
• Demonstration of Raman spectroscopy on DMSO using the developed fiber probes.
• Comparison of signal retrieval methods, highlighting the effectiveness of the double-clad fiber coupler.
• Significant reduction in fiber spectral background signal achieved with the fiber coupler.

Conclusions:

• Optically-poled double-clad fibers are effective for in-situ generation of light for Raman spectroscopy.
• The developed fiber Raman probes offer a compact and efficient solution for molecular analysis.
• The double-clad fiber coupler significantly improves the signal-to-noise ratio by minimizing spectral background.