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This work discusses the design and fabrication of a dual-plane terahertz (THz) hologram and an extended-depth-of-focus THz diffractive lens. The dual-plane THz hologram consists of 50 × 50 diffractive optical elements with identical element pixel size 1×1 mm, and the extended-depth-of-focus THz diffractive lens is designed with 25 concentric rings with identical ring width of 1 mm, resulting in same device dimension 50 mm × 50 mm. The height of the hologram pixels and concentric rings of the diffractive lens are optimized by nonlinear optimization algorithms with scalar diffraction theory based on Ray-Sommerfeld diffraction equation. Finite-Difference Time-Domain (FDTD) simulation results agree with optimization results obtained from the scalar diffraction theory for both the THz hologram and the THz diffractive lens. The demonstrated experimental results show that the proposed THz hologram and THz diffractive lens can generate the desired diffraction patterns. These diffractive structures have the potential to be applied in areas such as THz imaging, data storage, and displays.
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Recent advances in terahertz imaging: 1999 to 2021
Abstract We discuss the progress in the field of THz imaging based on time-domain spectroscopy during the last 20 years emphasizing several highlights. These include 3D mapping of the water distribution of plants, THz reflection imaging of samples with arbitrary shape, burn wound imaging and the early diagnosis of diabetic foot disease. These applications greatly benefit from the introduction of fibre-coupled THz time-domain system operated by rugged and portable femtosecond fibre-lasers. THz imaging is a versatile measurement method that has a plethora of practical applications and great promise for the future.
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- PAR ID:
- 10362503
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Applied Physics B
- Volume:
- 128
- Issue:
- 1
- ISSN:
- 0946-2171
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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