Focus quality in raster-scan imaging via a multimode fiber.

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Fiber Optics

Background:

• Multimode fibers (MMF) are used as minimally invasive imaging probes.
• Raster-scan imaging with MMF relies on wavefront shaping (WFS) to optimize foci at the fiber output.
• Real-world MMF applications often involve partial mode control and non-ideal input light conditions.

Purpose of the Study:

• To investigate the impact of input light position on WFS performance in a round-core MMF.
• To analyze the trade-offs between focus shape and contrast influenced by input position.
• To provide insights for optimizing MMF-based raster-scan microscopy.

Main Methods:

• Utilized wavefront shaping (WFS) techniques to control light propagation through a round-core MMF.
• Varied the input light position (center vs. edge) on the fiber facet.
• Analyzed the characteristics of the generated foci at the MMF output, including shape and contrast.

Main Results:

• Input light position significantly influences WFS outcomes in MMF.
• A center input position yields higher contrast foci, crucial for detailed imaging.
• An edge input position is more effective in mitigating focus aberrations.
• Demonstrated a clear trade-off between focus contrast and aberration reduction based on input position.

Conclusions:

• Input light positioning is a critical parameter for optimizing MMF-based raster-scan imaging.
• Understanding the center vs. edge input trade-off allows for tailored WFS strategies.
• These findings are essential for advancing high-field-of-view imaging applications using MMF probes.