Dual-modal all-fiber OCT needle probe integrated with FBG for simultaneous imaging and temperature sensing

Area of Science:

• Biomedical Engineering
• Optical Sensing
• Medical Imaging

Background:

• Simultaneous imaging and sensing are crucial for advanced biomedical applications.
• Existing probes often lack integrated dual-modal capabilities, necessitating complex setups.
• Fiber Bragg gratings (FBGs) offer potential for sensing, but integration with imaging modalities requires careful design.

Purpose of the Study:

• To design and fabricate a single-fiber needle probe for simultaneous optical coherence tomography (OCT) imaging and temperature sensing.
• To investigate the influence of FBG parameters on dual-modal performance.
• To establish optimal parameters for balancing imaging quality and sensing accuracy.

Main Methods:

• Fabrication of a single-fiber needle probe integrating a fiber Bragg grating (FBG).
• Design of the FBG Bragg wavelength to align with the OCT light source spectral bandwidth.
• Characterization of probe resolution, working distance, and temperature sensitivity.
• Evaluation of FBG reflectance impact on OCT imaging and sensing.

Main Results:

• The dual-modal probe achieved a lateral resolution of ~30 μm and a temperature sensitivity of 10.14 pm/℃.
• Limiting FBG reflectance to ≤24% was identified as a threshold for optimal performance.
• Successful demonstration of the probe's functionality in ex vivo mouse brains and porcine backfat.

Conclusions:

• The developed single-fiber probe successfully integrates OCT imaging and FBG-based temperature sensing.
• The findings provide a critical reference for optimizing dual-modal probes for biomedical applications.
• This technology holds promise for enhanced in vivo diagnostics and research.