Confocal microscopy using variable-focal-length microlenses and an optical fiber bundle

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Materials Science

Background:

• Confocal microscopy requires precise axial scanning for 3D imaging.
• Traditional methods often involve mechanical sample or objective movement, limiting speed and applicability in vivo.
• Variable-focal-length (VFL) microlenses offer electronic control over focus, potentially overcoming these limitations.

Purpose of the Study:

• To develop a high-throughput aperture array using VFL microlenses coupled to a fiber bundle.
• To demonstrate its application in a confocal imaging system for in vivo biological specimens.
• To evaluate the axial scanning capabilities and performance of the developed system.

Main Methods:

• VFL microlenses were fabricated using liquid-crystal films and patterned electrodes.
• Microlenses were individually coupled to a fiber bundle to form a controllable aperture array.
• The VFL microlens array and fiber bundle were integrated into a confocal microscopy system.
• Axial response was measured without mechanical stage or objective movement.

Main Results:

• A high-throughput aperture array with controllable aperture patterns was successfully created.
• The confocal system demonstrated electronic axial scanning capabilities.
• The axial response showed a Full Width at Half Maximum (FWHM) of approximately 16 micrometers.
• Asymmetric sidelobes were observed in the axial response.

Conclusions:

• Coupling VFL microlenses to fiber bundles provides a viable method for creating electronically controllable aperture arrays.
• This approach enables real-time, in vivo confocal imaging with axial scanning without mechanical components.
• The developed system shows promise for advanced biological imaging applications.