Focus scanning with feedback-control for fiber-optic nonlinear endomicroscopy.

Area of Science:

• Biomedical Optics
• Medical Devices
• Microscopy

Background:

• Fiber-optic endomicroscopes enable novel in vivo nonlinear optics applications.
• Current depth scanning methods using shape memory alloy (SMA) wires in miniature endomicroscopes have limitations in accuracy and reliability.
• Accurate depth control is crucial for advanced in vivo imaging.

Purpose of the Study:

• To develop a feedback-controlled SMA depth scanner for miniature fiber-optic endomicroscopes.
• To overcome the limitations of existing SMA depth scanning methods.
• To achieve accurate and robust depth control for in vivo nonlinear optical imaging.

Main Methods:

• A shape memory alloy (SMA) wire was used as the actuation mechanism.
• A Hall effect sensor was integrated for real-time tracking of SMA wire contraction.
• A feedback control loop was implemented to achieve precise motion control.
• Depth-resolved nonlinear endomicroscopic imaging was used for verification.

Main Results:

• The SMA depth scanner achieved up to 490 µm travel.
• Open-loop operation allowed movement exceeding 350 µm within one second.
• Feedback control enabled submicron positioning accuracy and superior stability.
• High-precision positioning was validated through imaging of mouse brain samples.

Conclusions:

• The feedback-controlled SMA depth scanner provides accurate and stable depth control for fiber-optic endomicroscopes.
• This technology enhances the capabilities of in vivo nonlinear optical imaging.
• The developed scanner is suitable for high-precision applications like neuroimaging.