Miniature varifocal objective lens for endomicroscopy.

Area of Science:

• Optical Engineering
• Biomedical Imaging
• Microscopy

Background:

• Endoscopic imaging requires compact optical systems with adjustable parameters.
• Traditional endoscopic lenses often rely on mechanical components for magnification and field of view (FOV) changes, limiting miniaturization and robustness.
• Wavelength division multiplexing (WDM) offers a potential method for optical control without mechanical actuation.

Purpose of the Study:

• To develop and demonstrate a miniature catadioptric lens for endoscopic imaging.
• To achieve variable magnification and FOV control without mechanical adjustments.
• To validate the lens's performance in reflectance and multiphoton fluorescence imaging applications.

Main Methods:

• Design and fabrication of a miniature catadioptric lens utilizing WDM principles.
• Characterization of lens magnification across different wavelengths (406-750 nm and 800 nm).
• Demonstration of imaging capabilities using reflectance and multiphoton fluorescence microscopy on unstained mouse tissues.

Main Results:

• The catadioptric lens achieved magnifications of approximately -1.5× (406-750 nm) and -0.2× (800 nm).
• Variable magnification and FOV were demonstrated without any mechanical reconfiguration of optical elements.
• Successful large-FOV (1.3 mm) reflectance imaging and high-resolution (0.57 μm) multiphoton fluorescence imaging of mouse tissues were performed.

Conclusions:

• A novel, mechanically tunable miniature catadioptric lens for endoscopic imaging based on WDM is presented.
• The lens offers a compact and robust solution for variable magnification and FOV control in endoscopic applications.
• The demonstrated imaging capabilities highlight its potential for advanced in vivo tissue diagnostics.