Single-shot common-path off-axis dual-wavelength digital holographic microscopy

Area of Science:

• Optics and Photonics
• Microscopy
• Biophysics

Background:

• Digital holographic microscopy (DHM) is a powerful tool for 3D imaging.
• Traditional DHM systems often face limitations in phase range and stability.
• Accurate measurement of refractive index and physical thickness is crucial in various scientific fields.

Purpose of the Study:

• To develop a single-shot, common-path, off-axis, dual-wavelength digital holographic microscopic system.
• To expand the phase range for analyzing stepped microstructures.
• To achieve simultaneous measurement of refractive index and physical thickness of specimens.

Main Methods:

• Utilized a cube beam splitter for a common-path, self-interference configuration.
• Employed two laser wavelengths (532 nm and 632.8 nm) for dual-wavelength illumination.
• Implemented phase aberration compensation based on principal component analysis (PCA) for phase extraction from a single hologram.

Main Results:

• Successfully demonstrated a dual-wavelength DHM system with an expanded phase range.
• Achieved simultaneous measurement of refractive index and physical thickness.
• The common-path design resulted in high temporal phase stability and reduced sensitivity to vibrations.

Conclusions:

• The developed dual-wavelength DHM system offers significant advantages in phase range and measurement accuracy.
• The system's stability and robustness make it suitable for analyzing complex microstructures and biological samples.
• Validated the system's performance using microsphere beads and living plant cells.