Lateral shearing common-path digital holographic microscopy based on a slightly trapezoid Sagnac interferometer

Area of Science:

• Optics and Photonics
• Microscopy Techniques
• Interferometry

Background:

• Digital holographic microscopy (DHM) offers advanced imaging capabilities.
• Common-path interferometers enhance stability by minimizing optical path differences.
• Lateral shearing interferometers provide phase information through beam splitting.

Purpose of the Study:

• To propose a compact and easily aligned lateral shearing common-path digital holographic microscopy system.
• To demonstrate precise control over the off-axis angle and maintain image quality.
• To validate the system's capability for imaging static and dynamic specimens.

Main Methods:

• Utilizing a slightly trapezoidal Sagnac interferometer to generate laterally sheared beams.
• Forming an off-axis geometry for digital hologram recording.
• Employing identical optical elements for both beams in opposite directions.
• Conducting experiments without vibration isolation to assess temporal stability.

Main Results:

• Achieved a temporal stability of approximately 0.011 radians without vibration isolation.
• Demonstrated easy and quantitative control over the off-axis angle.
• Maintained high image quality comparable to simpler lateral shearing interferometers.
• Successfully performed measurements on both static and dynamic specimens.

Conclusions:

• The proposed lateral shearing common-path DHM is compact, stable, and easy to align.
• The system offers precise control and high-quality imaging for various applications.
• This technique is applicable for characterizing both static and dynamic samples effectively.