Photoacoustic endoscopic probe based on lens scanning using a laterally tunable electrowetting liquid lens

Area of Science:

• Biomedical Optics
• Optical Engineering
• Medical Imaging

Background:

• Existing photoacoustic endoscopy (PAE) systems often use external scanning, leading to bulky and complex probes.
• This complexity limits the widespread adoption and miniaturization of PAE technology for various endoscopic applications.

Purpose of the Study:

• To develop a compact and efficient scanning mechanism for PAE.
• To eliminate the need for external scanning mirrors by integrating direct focal point shifting capabilities into the endoscopic probe.

Main Methods:

• A laterally tunable liquid lens was designed and implemented for direct focal point shifting.
• Ray tracing analysis and experimental validation were performed to characterize the lens's tunability.
• The liquid lens was integrated into a PAE probe for performance evaluation.

Main Results:

• The tunable liquid lens demonstrated significant axial shifting (20 mm) and lateral tilting (4.42°) at 45.3 Vrms.
• Integration into a PAE probe resulted in a nearly fourfold increase in photoacoustic signal intensity compared to conventional stage scanning.
• The developed system showed enhanced performance for photoacoustic imaging applications.

Conclusions:

• The proposed laterally tunable liquid lens offers a compact and effective solution for PAE.
• This innovation paves the way for miniaturized PAE systems with improved imaging capabilities.
• The technology holds substantial promise for advancing endoscopic diagnostic tools.