Allocation of spatial single-mode from multimode oscillation using temporal phase unwrapping in digital holographic...

Area of Science:

• Optical Metrology
• Vibration Analysis
• Digital Holography

Background:

• Multimode resonant oscillations present challenges in precise analysis.
• Digital holographic interferometry offers potential for dynamic measurements.
• Temporal phase unwrapping is crucial for accurate displacement reconstruction.

Purpose of the Study:

• To develop and validate a method for reconstructing and analyzing multimode resonant oscillations.
• To enable the separation of single-mode vibrations from complex dynamic responses.
• To apply temporal phase unwrapping to time-dependent holographic data.

Main Methods:

• Utilized temporal phase unwrapping algorithm in digital holographic interferometry.
• Employed a scanning procedure with a CCD camera (15 f/s) to capture vibration data.
• Applied Fourier transform and inverse Fourier transform for mode separation.
• Acquired thousands of holograms for time-dependent phase reconstruction.

Main Results:

• Successfully reconstructed time-dependent displacement of object points.
• Allocated spatial single-mode distributions from multimode vibrations.
• Demonstrated the method's capability to analyze multimode vibrations on a metal plate.
• Obtained spatial allocation of each single-mode oscillation over time.

Conclusions:

• The proposed temporal phase unwrapping method is effective for analyzing multimode vibrations.
• The technique allows for the isolation and spatial mapping of individual vibration modes.
• Limitations and applicability of the method were discussed for future research.