Versatile optical frontends for multicolor fluorescence imaging with miniaturized lensless sensors

Area of Science:

• Optical Engineering
• Biomedical Imaging
• Photonics

Background:

• Lensless imaging offers compact fluorescence sensors for in vivo imaging and point-of-care diagnostics.
• Conventional filters in these systems struggle with angle of incidence (AOI) sensitivity.
• Fiber optic plates (FOPs) can mitigate off-axis light bleed-through and enhance resolution.

Purpose of the Study:

• To analyze and optimize FOPs for lensless fluorescence imaging systems.
• To investigate the trade-offs between FOP numerical aperture (NA), collection efficiency, and image resolution.
• To demonstrate adaptable optical frontend designs for various lensless imaging applications.

Main Methods:

• Simulations were used to analyze FOP NA effects on performance.
• Two optical frontend designs were optimized using FOPs with different NA values (8.3° and 45.7°).
• Interference filters were coated on both sides of the FOP to address internal scattering.

Main Results:

• Higher NA FOPs significantly increase light collection but reduce resolution at longer working distances.
• A low-NA FOP design achieved 110-µm resolution at a 1-mm working distance for three-color fluorescence imaging.
• Coating filters on both FOP sides is crucial for consistent performance across all AOIs.

Conclusions:

• FOPs are effective in improving lensless fluorescence imaging systems.
• Design choices involving FOP NA allow for adaptable performance tailored to specific applications.
• This versatile optical frontend supports diverse fluorophores, illumination, and lensless techniques.