Fast photoacoustic-guided depth-resolved Raman spectroscopy: a feasibility study

Area of Science:

• Spectroscopy
• Biomedical Optics
• Photoacoustics

Background:

• Depth-resolved Raman spectroscopy is crucial for analyzing layered materials and biological tissues.
• Accurate depth localization remains a challenge for conventional Raman spectroscopy.
• Faster measurement speeds are needed for practical in-situ and in-vivo applications.

Purpose of the Study:

• To introduce and demonstrate photoacoustic-guided Raman spectroscopy (PARS) for fast, depth-resolved Raman measurements.
• To achieve accurate depth localization using photoacoustic signals.
• To explore the potential of PARS for biomedical applications, including cancer diagnostics.

Main Methods:

• Development of a synergic photoacoustic-Raman probe.
• Experimental demonstration using a three-layer agar phantom.
• Utilizing photoacoustic time-of-flight for depth localization and guidance.

Main Results:

• Successful simultaneous acquisition of photoacoustic and Raman signals.
• Demonstrated strong correlation between photoacoustic signals and depth.
• Achieved significantly faster operation speeds compared to conventional methods.
• Validated accurate depth localization capabilities.

Conclusions:

• PARS enables rapid and accurate depth-resolved Raman measurements.
• The developed probe and method show high potential for biomedical applications.
• Future integration with advanced optical focusing could enhance PARS for in-vivo cancer diagnostics.