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Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization
Published on: July 5, 2016
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Real-time terahertz digital holography with a quantum cascade laser
Massimiliano Locatelli1,2, Marco Ravaro1,2, Saverio Bartalini1,2
1INO-CNR, Istituto Nazionale di Ottica, Largo E. Fermi 6, Firenze, I-50125, Italia.
Scientific Reports
|August 29, 2015
Summary
This study introduces real-time terahertz (THz) digital holography (DH) for material inspection. This breakthrough enables rapid, high-resolution imaging of objects, overcoming previous limitations in THz coherent imaging.
Area of Science:
- Optics and Photonics
- Terahertz (THz) Science and Technology
- Imaging and Sensing
Background:
- Terahertz (THz) coherent imaging offers unique material penetration capabilities for applications in non-destructive testing, security, and biomedicine.
- Previous THz imaging methods were hindered by slow scanning, point detection, and inadequate coherent sources.
- Digital holography (DH) provides a powerful framework for wavefront reconstruction but faced challenges at THz frequencies.
Purpose of the Study:
- To demonstrate real-time digital holography (DH) at terahertz (THz) frequencies.
- To overcome the limitations of traditional THz coherent imaging techniques.
- To enable rapid, full-field holographic recording of dynamic scenes at THz wavelengths.
Main Methods:
- Utilized a quantum cascade laser (QCL) for a high spectral purity and mW output power THz source.
- Employed a high-sensitivity and resolution microbolometric array for THz detection.
- Implemented a digital holography (DH) setup for one-shot recording of phase and amplitude information.
Main Results:
- Achieved real-time THz digital holography (DH) with a single exposure.
- Successfully recorded both phase and amplitude information of samples in reflection and transmission.
- Demonstrated a 200-fold reduction in sensitivity to mechanical vibrations compared to visible light DH.
- Observed a significantly enlarged field of view compared to visible light DH.
Conclusions:
- Real-time THz DH overcomes previous limitations, enabling rapid and robust coherent imaging.
- The developed THz DH system offers enhanced stability and a wider field of view for practical applications.
- This technology paves the way for unprecedented holographic recording of dynamic real-world scenes in the THz range.
