Enhanced signal coupling in wide-field fiber-coupled imagers

Area of Science:

• Optical engineering
• Imaging systems
• Micro-optics

Background:

• High-performance imaging systems often use monocentric lenses with curved image surfaces coupled to sensors via optical fiber bundles.
• Refraction at angled fiber input facets limits the field of view (FOV) and edge spatial resolution.
• Existing systems struggle to capture wide-angle images without compromising peripheral clarity.

Purpose of the Study:

• To investigate the use of curved beam deflectors to increase the FOV and improve edge spatial resolution in monocentric imagers.
• To overcome the limitations imposed by fiber optic coupling in wide-angle imaging.
• To enhance the performance of fiber-coupled imaging systems for broader applications.

Main Methods:

• Embossing a refractive microprism array with varying prism angles onto a thin layer of SU-8 photopolymer.
• Integrating the microprism array near the focal surface of a fiber-coupled monocentric singlet lens.
• Conducting proof-of-principle experiments to measure the impact on FOV and spatial resolution.

Main Results:

• Demonstrated an increase in the field of view from approximately 60° to over 90° (full width at half maximum intensity).
• Achieved a 50% increase in the field of view in a local region using the embossed microprism array.
• Showcased the effectiveness of microprisms in maintaining optical coupling across a wider angular range.

Conclusions:

• Curved beam deflectors, specifically embossed refractive microprism arrays, can significantly enhance the field of view in fiber-coupled monocentric imaging systems.
• This approach offers a practical method to improve spatial resolution at the edges of the field of view.
• The findings present a viable strategy for developing next-generation wide-angle imaging devices.