Fast volumetric fluorescence imaging with multimode fibers.

Area of Science:

• Optical Engineering
• Biomedical Imaging
• Microscopy

Background:

• Multimode fiber (MMF) endoscopes offer compact imaging solutions but suffer from optical aberrations.
• Wavefront shaping techniques can correct these aberrations, but often require lengthy calibration procedures.
• Existing methods struggle with accurate focusing at various depths and fast imaging speeds.

Purpose of the Study:

• To propose and validate a novel, rapid calibration method for MMF endoscopy.
• To achieve accurate focusing and high-resolution imaging at depth using wavefront shaping.
• To demonstrate the potential for volumetric tissue imaging with improved speed and performance.

Main Methods:

• Employed a digital micromirror device (DMD) for wavefront shaping.
• Developed an automated single calibration step (SCMFI) to correct optical misalignment.
• Utilized rapid switching of holographic patterns for dynamic focusing at different depths.

Main Results:

• Achieved near diffraction-limited focusing up to 110 µm depth with 1.4 µm lateral resolution.
• Demonstrated calibration speeds one to two orders of magnitude faster than existing methods.
• Successfully imaged fluorescent beads in a 3D matrix, showing excellent power penetration and focusing.

Conclusions:

• The single calibration multimode fiber imaging (SCMFI) method significantly enhances MMF endoscope performance.
• SCMFI offers a fast and accurate solution for deep tissue imaging.
• This technology enables future advancements in high-speed, volumetric tissue endoscopy.