Fabrication and testing of highly efficient resonance domain diffractive optical elements

Recently, one of the most commonly discussed applications of terahertz radiation is wireless telecommunication. It is believed that the future 6G systems will utilize this frequency range. Although the exact technology of future telecommunication systems is not yet known, it is certain that methods for increasing their bandwidth should be investigated in advance. In this paper, we present the diffractive optical elements for the frequency division multiplexing of terahertz waves. The structures have been designed as a combination of a binary phase grating and a converging diffractive lens. The grating allows for differentiating the frequencies, while the lens assures separation and focusing at the finite distance. Designed structures have been manufactured from polyamide PA12 using the SLS 3D printer and verified experimentally. Simulations and experimental results are shown for different focal lengths. Moreover, parallel data transmission is shown for two channels of different carrier frequencies propagating in the same optical path. The designed structure allowed for detecting both signals independently without observable crosstalk. The proposed diffractive elements can work in a wide range of terahertz and sub-terahertz frequencies, depending on the design assumptions. Therefore, they can be considered as an appealing solution, regardless of the band finally used by the future telecommunication systems.

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Nanooptical elements for visual verification

Scientific Reports ◽

10.1038/s41598-021-81950-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alexander Goncharsky ◽

Anton Goncharsky ◽

Dmitry Melnik ◽

Svyatoslav Durlevich

Keyword(s):

Electron Beam ◽

Electron Beam Lithography ◽

Mass Production ◽

Optical Element ◽

Visual Image ◽

Zero Order ◽

Diffractive Optical Elements ◽

Optical Elements ◽

Standard Equipment ◽

Diffractive Element

AbstractThis paper focuses on the development of flat diffractive optical elements (DOEs) for protecting banknotes, documents, plastic cards, and securities against counterfeiting. A DOE is a flat diffractive element whose microrelief, when illuminated by white light, forms a visual image consisting of several symbols (digits or letters), which move across the optical element when tilted. The images formed by these elements are asymmetric with respect to the zero order. To form these images, the microrelief of a DOE must itself be asymmetric. The microrelief has a depth of ~ 0.3 microns and is shaped with an accuracy of ~ 10–15 nm using electron-beam lithography. The DOEs developed in this work are securely protected against counterfeiting and can be replicated hundreds of millions of times using standard equipment meant for the mass production of relief holograms.

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Mobile snapshot hyperspectral imaging device for skin evaluation using diffractive optical elements

Skin Research and Technology ◽

10.1111/srt.12991 ◽

2021 ◽

Author(s):

Christian Kern ◽

Uwe Speck ◽

Rainer Riesenberg ◽

Carina Reble ◽

Georg Khazaka ◽

...

Keyword(s):

Hyperspectral Imaging ◽

Diffractive Optical Elements ◽

Optical Elements ◽

Imaging Device

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