Terahertz multiwavelength phase imaging without 2pi ambiguity

Area of Science:

• Optics and Photonics
• Terahertz Spectroscopy
• Image Processing

Background:

• Terahertz (THz) imaging is valuable for non-destructive analysis.
• Phase imaging in THz applications often requires complex phase unwrapping.
• Noise reduction is crucial for enhancing image quality in THz imaging.

Purpose of the Study:

• To present a novel multiwavelength terahertz phase imaging method.
• To overcome limitations of single-wavelength THz phase imaging, such as limited optical length and phase discontinuity detection.
• To demonstrate an effective noise reduction strategy for THz phase imaging.

Main Methods:

• Utilizing multiple wavelengths within the terahertz spectrum for phase imaging.
• Developing a phase data processing technique that avoids conventional phase unwrapping.
• Implementing noise reduction algorithms tailored for multiwavelength THz data.

Main Results:

• The multiwavelength approach allows imaging of objects with a larger optical length than achievable with the longest single wavelength.
• The method successfully detects phase discontinuities without traditional phase unwrapping.
• Significant reduction in noise background was observed in experimental measurements.
• Two experimental examples validated the method's effectiveness.

Conclusions:

• Multiwavelength terahertz phase imaging is a viable and efficient technique.
• The presented method simplifies phase data processing in THz imaging.
• This approach enhances imaging capabilities and reduces noise in terahertz applications.