Design and implementation of fiber-based multiphoton endoscopy with microelectromechanical systems scanning

Area of Science:

• Biomedical Optics
• Microscopy
• Optical Engineering

Background:

• Multiphoton microscopy offers deep tissue imaging capabilities.
• Miniaturized endoscopic systems are crucial for in vivo biological studies.
• Photonic crystal fibers provide unique light delivery and collection properties.

Purpose of the Study:

• To develop and characterize a compact multiphoton endoscopy system.
• To evaluate the performance of microelectromechanical systems (MEMS) scanners and double-cladding photonic crystal fiber (DCPCF) for endoscopic imaging.
• To optimize probe design for high-resolution multiphoton imaging.

Main Methods:

• Integration of a two-axis MEMS mirror with a 2-mm diameter and 20-degree scanning angle.
• Utilized DCPCF, comparing its dispersion, attenuation, and coupling efficiency against standard fibers.
• Investigated three probe configurations, selecting a two-lens design for optimal performance.
• Applied grating pairs for dispersion compensation in the DCPCF.

Main Results:

• The MEMS scanner achieved a maximum of 720x720 resolvable spots, indicating high-resolution imaging potential.
• DCPCF demonstrated high collection efficiency, with dispersion successfully compensated.
• The two-lens probe configuration offered superior imaging quality and packaging flexibility.
• Successful imaging of fluorescent microspheres and bovine knee joint cartilage was achieved.

Conclusions:

• The developed multiphoton endoscopy system, integrating MEMS scanning and DCPCF, enables high-resolution imaging.
• The optimized probe design and fiber characteristics are suitable for advanced endoscopic applications.
• This system holds promise for in vivo microscopic examination of biological tissues.