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Terahertz near-field microscopy based on an air-plasma dynamic aperture
Xin-Ke Wang1, Jia-Sheng Ye1, Wen-Feng Sun1
1Beijing Key Laboratory of Metamaterials and Devices, Key Laboratory of Terahertz Optoelectronics Ministry of Education, Department of Physics, Capital Normal University, Beijing, 100048, China.
Light, Science & Applications
|May 7, 2022
Summary
A novel terahertz (THz) near-field microscopy technique uses an air-plasma dynamic aperture for sub-wavelength imaging without sample proximity. This method avoids sample damage and broadens material applicability in THz microscopy.
Area of Science:
- Optics and Photonics
- Materials Science
- Physics
Background:
- Terahertz (THz) near-field microscopy offers sub-wavelength imaging capabilities crucial for research and industry.
- Conventional THz near-field microscopy is limited by the need for close proximity between the THz detector/source and the sample, restricting sample types.
Purpose of the Study:
- To develop a non-contact THz near-field microscopy technique.
- To overcome the limitations of sample proximity in existing THz near-field microscopy methods.
- To achieve quasi sub-wavelength resolution imaging without damaging the sample.
Main Methods:
- A novel air-plasma dynamic aperture was engineered using two overlapping, mutually perpendicular air-plasmas.
- This plasma configuration formed a cross-filament above the sample, modulating the incident THz beam.
- The system achieved THz imaging without any physical contact with the sample surface.
Main Results:
- Quasi sub-wavelength resolution (approximately λ/2) THz imaging was demonstrated.
- The technique successfully imaged diverse materials, including metallic, semiconductor, plastic, and greasy samples.
- Sample damage from air-plasmas was successfully avoided.
Conclusions:
- The developed air-plasma dynamic aperture technique enables non-contact THz near-field imaging.
- This advancement overcomes key limitations of conventional THz microscopy, expanding its applicability.
- The technique is poised to accelerate progress in THz microscopy for various scientific and industrial applications.
