Implementation of phase-shift patterns using a holographic projection system with phase-only diffractive optical elements

2011 ◽  
Vol 50 (20) ◽  
pp. 3646 ◽  
Author(s):  
Wei-Feng Hsu ◽  
Yu-Wen Chen ◽  
Yuan-Hong Su
Keyword(s):  
Phase Shift ◽  
Diffractive Optical Elements ◽  
Optical Elements ◽  
Projection System

scholarly journals Diffractive optics based automotive lighting system

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Muhammad Shaukat Khan ◽  
Woheeb Muhammad Saeed ◽  
Bernhard Roth ◽  
Roland Lachmayer
Keyword(s):  
Optical Design ◽  
Field Of View ◽  
Automotive Application ◽  
Diffractive Optical Elements ◽  
Lighting System ◽  
Optical Elements ◽  
Projection System ◽  
Road Users ◽  
Projection Screen ◽  
Information Projection

AbstractInformation projection using laser-based illumination systems in the automotive area is of keen interest to enhance communication between road users. Numerous work on laser-based front end projection employing refractive and reflective optics has been reported so far, while for rear end illumination efforts are more scarce and a different optical design concept due to limited volumetric size and field of view regulations is required. Here, we report on a new and versatile approach for a laser-based rear end lighting system for automotive application which enables projection of information or signals to support other road users. The design is based on thin diffractive optical elements projecting the desired patterns upon illumination. Also, for protection of the road users from the steering laser beam, a diffusive back projection screen is designed to project information while fulfilling both the field of view and safety requirements. The projection system is based on a periodic diffusive structure made of an array of biconic lenses with sizes in the millimeter range. The field of view (FOV) from the simulated lens arrays complies with the angular requirements set by the Economic Commission for Europe (ECE). As a proof of concept, the diffusive screen is fabricated using microfabrication technology and characterized. In future, the screen will be combined with thin diffractive optical elements to realize an entire integrated projection system.

scholarly journals Frequency Division Multiplexing of Terahertz Waves Realized by Diffractive Optical Elements

2021 ◽  
Vol 11 (14) ◽  
pp. 6246
Author(s):  
Paweł Komorowski ◽  
Patrycja Czerwińska ◽  
Mateusz Kaluza ◽  
Mateusz Surma ◽  
Przemysław Zagrajek ◽  
...  
Keyword(s):  
Frequency Division Multiplexing ◽  
Diffractive Optical Elements ◽  
Frequency Division ◽  
Terahertz Waves ◽  
Optical Elements ◽  
Telecommunication Systems ◽  
Wide Range ◽  
The Future ◽  
Wireless Telecommunication ◽  
Finite Distance

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.

scholarly journals Nanooptical elements for visual verification

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.

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

2021 ◽  
Author(s):  
Christian Kern ◽  
Uwe Speck ◽  
Rainer Riesenberg ◽  
Carina Reble ◽  
Georg Khazaka ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Diffractive Optical Elements ◽  
Optical Elements ◽  
Imaging Device

scholarly journals Absolute Phase Retrieval Using One Coded Pattern and Geometric Constraints of Fringe Projection System

2018 ◽  
Vol 8 (12) ◽  
pp. 2673 ◽  
Author(s):  
Xu Yang ◽  
Chunnian Zeng ◽  
Jie Luo ◽  
Yu Lei ◽  
Bo Tao ◽  
...  
Keyword(s):  
Phase Shift ◽  
Phase Retrieval ◽  
Code Word ◽  
Geometric Constraints ◽  
Fringe Projection ◽  
Average Intensity ◽  
Fringe Order ◽  
Projection System ◽  
Absolute Phase ◽  
Three Phase

Fringe projection technologies have been widely used for three-dimensional (3D) shape measurement. One of the critical issues is absolute phase recovery, especially for measuring multiple isolated objects. This paper proposes a method for absolute phase retrieval using only one coded pattern. A total of four patterns including one coded pattern and three phase-shift patterns are projected, captured, and processed. The wrapped phase, as well as average intensity and intensity modulation, are calculated from three phase-shift patterns. A code word encrypted into the coded pattern can be calculated using the average intensity and intensity modulation. Based on geometric constraints of fringe projection system, the minimum fringe order map can be created, upon which the fringe order can be calculated from the code word. Compared with the conventional method, the measurement depth range is significantly improved. Finally, the wrapped phase can be unwrapped for absolute phase map. Since only four patterns are required, the proposed method is suitable for real-time measurement. Simulations and experiments have been conducted, and their results have verified the proposed method.

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