Fast and pure phase-shifting off-axis holographic microscopy with a digital micromirror device

Area of Science:

• Microscopy
• Optical Physics
• Biophysics

Background:

• Digital holographic microscopy (DHM) is a powerful tool for quantitative phase imaging.
• Traditional phase-shifting methods in DHM can be complex and time-consuming.
• There is a need for simpler, faster phase-shifting techniques for dynamic imaging.

Purpose of the Study:

• To develop and validate a novel phase-shifting digital holographic microscopy technique.
• To enable high-speed, quantitative phase imaging of dynamic biological samples.
• To offer a simpler and more compatible alternative to existing phase-shifting methods.

Main Methods:

• Utilized a digital micromirror device (DMD) for precise, phase-only shifting of the reference wave.
• Employed a monomode fiber to couple the beam, ensuring a constant phase shift across the hologram.
• Implemented an off-axis configuration for holographic recording.

Main Results:

• Successfully demonstrated a phase-shifting DHM technique with a DMD.
• Achieved a constant phase shift across all hologram pixels via fiber coupling.
• Validated the technique by imaging living *Paramecia caudata* at high frame rates.

Conclusions:

• The presented phase-shifting DHM method is simple, robust, and compatible with high-speed cameras.
• This technique is highly suitable for observing fast dynamic processes in biological samples.
• The DMD-based approach offers significant advantages for real-time holographic microscopy.