scholarly journals Neural-network based approach to optimize THz computer generated holograms

2021 ◽  
Vol 13 (4) ◽  
pp. 88
Author(s):  
Mateusz Surma ◽  
Mateusz Kaluza ◽  
Patrycja Czerwińska ◽  
Paweł Komorowski ◽  
Agnieszka Siemion
Keyword(s):  
Neural Network ◽  
Optical Element ◽  
Computational Design ◽  
Additive Manufacture ◽  
Diffractive Optical Elements ◽  
Terahertz Waves ◽  
Neural Network Approach ◽  
Optical Elements ◽  
Industrial Sectors ◽  
Terahertz Technology

Terahertz (THz) optics often encounters the problem of small f number values (elements have relatively small diameters comparing to focal lengths). The need to redirect the THz beam out of the optical axis or form particular intensity distributions resulted in the application of iterative holographic methods to design THz diffractive elements. Elements working on-axis do not encounter significant improvement while using iterative holographic methods, however, for more complicated distributions the difference becomes meaningful. Here, we propose a totally different approach to design THz holograms, utilizing a neural network based algorithm, suitable also for complicated distributions. Full Text: PDF ReferencesY. Tao, A. Fitzgerald and V. Wallace, "Non-Contact, Non-Destructive Testing in Various Industrial Sectors with Terahertz Technology", Sensors, 20(3), 712 (2020). CrossRef J. O'Hara, S. Ekin, W. Choi and I. Song, "A Perspective on Terahertz Next-Generation Wireless Communications", Technologies, 7(2), 43 (2019). CrossRef L. Yu et al., "The medical application of terahertz technology in non-invasive detection of cells and tissues: opportunities and challenges", RSC Advances, 9(17), 9354 (2019). CrossRef A. Siemion, "The Magic of Optics—An Overview of Recent Advanced Terahertz Diffractive Optical Elements", Sensors, 21(1), 100 (2020). CrossRef A. Siemion, "Terahertz Diffractive Optics—Smart Control over Radiation", J. Infrared Millim. Terahertz Waves, 40(5), 477 (2019). CrossRef M. Surma, I. Ducin, P. Zagrajek and A. Siemion, "Sub-Terahertz Computer Generated Hologram with Two Image Planes", Appl. Sci., 9(4), 659 (2019). CrossRef S. Banerji and B.Sensale-Rodriguez, "A Computational Design Framework for Efficient, Fabrication Error-Tolerant, Planar THz Diffractive Optical Elements", Sci. Rep., 9(1), 5801 (2019). CrossRef J. Sun and F. Hu, "Three-dimensional printing technologies for terahertz applications: A review", Int. J. RF. Microw. C. E., 30(1) (2020). CrossRef E. Castro-Camus, M. Koch and A. I. Hernandez-Serrano, "Additive manufacture of photonic components for the terahertz band", J. Appl. Phys., 127(21), 210901 (2020). CrossRef https://community.wolfram.com/groups/-/m/t/2028026?p_%20479%20p_auth=blBtLb5d DirectLink P. Komorowski, et al., "Three-focal-spot terahertz diffractive optical element-iterative design and neural network approach", Opt. Express, 29(7), 11243-11253 (2021) CrossRef M. Sypek, "Light propagation in the Fresnel region. New numerical approach", Opt. Commun., 116(1-3), 43 (1995). CrossRef

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 On a problem of the synthesis of binary nano-optical elements

2016 ◽  
pp. 415-424
Author(s):  
А.А. Гончарский ◽  
С.Ю. Серёжников
Keyword(s):  
Electron Beam ◽  
Augmented Reality ◽  
Electron Beam Lithography ◽  
Optical Element ◽  
Diffractive Optical Elements ◽  
Partial Loss ◽  
Optical Elements ◽  
Optical Images ◽  
Augmented Reality Technology ◽  
Security Label

В рамках широко распространенной технологии Augmented Reality обсуждается возможность контроля подлинности защитных оптических меток на основе бинарных нанооптических элементов. С помощью смартфона фотографируют изображение защитной метки. Полученное изображение интерпретируется как дифракционный оптический элемент. В приближении Френеля рассчитывают изображение, формируемое дифракционным оптическим элементом, которое используют для идентификации подлинности защитной метки. Защитная метка представляет собой фазовый оптический элемент, глубина микрорельефа которого не превышает 0.5 мкм. Нанооптические элементы изготавливаются с помощью электроннолучевой литографии. Разработанные нанооптические элементы устойчивы к частичному повреждению микрорельефа и могут быть использованы для идентификации банкнот, документов и др. This paper deals with optical security label identification technology as a part of augmented reality technology. Security labels are based on binary nanooptical elements and are photographed using a smartphone. Photographed images are interpreted as diffractive optical elements. Optical images formed by these diffractive elements are computed using the Fresnel approximation. These images are used to identify the security labels. A security label consists of a phase optical element whose microrelief height is of no more than 0.5 $\mu$m. Nanooptical elements are manufactured using electron-beam lithography. The optical security labels are resistant against microrelief damages and can withstand partial loss of an image. The optical elements developed can be used to protect and identify banknotes, documents, etc.

scholarly journals Optimization of THz diffractive optical elements thickness

2018 ◽  
Vol 10 (4) ◽  
pp. 115 ◽  
Author(s):  
Mateusz Surma ◽  
Izabela Ducin ◽  
Maciej Sypek ◽  
Przemyslaw Zagrajek ◽  
Agnieszka Siemion
Keyword(s):  
Materials Science ◽  
Phase Distribution ◽  
Extreme Ultraviolet ◽  
Fresnel Lens ◽  
Optical Devices ◽  
Terahertz Wave ◽  
Diffractive Optical Elements ◽  
Terahertz Waves ◽  
Optical Elements ◽  
Absorbing Materials

Diffractive optical elements (DOEs) are strictly related to the design wavelength due to the fact that they must introduce particular phase delay of the wavefront propagating through the structure. Mostly the attenuation of the material is not taken into account. In this article we propose to optimize thickness of the DOE by reducing introduced phase retardation but also attenuation. The efficiency of DOEs is determined by the method of coding phase distribution and can be easily measured by using diffraction orders of corresponding diffraction grating. Here, we analyze binary phase diffraction gratings with assumed attenuation. Full Text: PDF ReferencesJ.-L. Coutaz, Optoélectronique térahertz (Les Ulis CEDEX A, France, EDP Sciences 2012). DirectLink D. Headland, Y. Monnai, D. Abbott, C. Fumeaux,and W. Withayachumnankul, "Tutorial: Terahertz beamforming, from concepts to realizations", APL Photonics 3, 5 (2018). CrossRef S. F. Busch, M. Weidenbach, M. Frey, F. Schäfer, T. Probst, nd M. Koch, "A 3D-Printable Polymer-Metal Soft-Magnetic Functional Composite—Development and Characterization", Journal of Infrared, Millimeter, and Terahertz Waves 35, 12 (2014) CrossRef A. Siemion, P. Kostrowiecki-Lopata, A. Pindur, P. Zagrajek, M. Sypek, "Paper on Designing Costless THz Paper Optics", Advances in Materials Science and Engineering 2016, 9615698 (2016). CrossRef A. Siemion, A. Siemion, M. Makowski, J. Suszek, J. Bomba, A. Czerwinski, F. Garet, J.-L. Coutaz, and M. Sypek, "Diffractive paper lens for terahertz optics", Opt. Lett. 37, 4320–4322 (2012). CrossRef J.-L. Coutaz, F. Garet, E. Bonnet, A. V. Tishchenko, O. Parriaux, and M. Nazarov, "Grating Diffraction Effects in the THz Domain", Acta Phys. Pol. A 107, 26-37 (2005). CrossRef M. S. Heimbeck, P. J. Reardon, J. Callahan, and H. O. Everitt, "Transmissive quasi-optical Ronchi phase grating for terahertz frequencies", Opt. Lett. 35, 21 (2010). CrossRef D. Li, S. Shu, F. Li, G. Ma, Y. Dai, and H. Ma, "Anomalous transmission of terahertz wave through one-dimensional lamellar metallic grating", Opt. Commun. 284, 10-11 (2011). CrossRef X. Li, and S. F. Yu, "Diffraction Characteristics of Concentric Circular Metal Grating Operating at Terahertz Regime", IEEE Journal of Quantum Electronics 46, 6 (2010). CrossRef B. Nöhammer, C. David, J. Gobrecht, and H. P. Herzig, "Optimized staircase profiles for diffractive optical devices made from absorbing materials", Opt. Lett. 28(13), 1087-1089 (2003). CrossRef V. Deuter, M. Grochowicz, S. Brose, J. Biller, S. Danylyuk, T. Taubner, D. Grutzmacher, and L. Juschkin, "Holographic masks for computational proximity lithography with EUV radiation", International Conference on Extreme Ultraviolet Lithography 2018 10809, 108091A (2018). CrossRef J. W. Goodman, Introduction to Fourier optics (Greenwood Village, USA, Roberts & Company Publishers 2005). DirectLink W. B. Veldkamp, "Optimized staircase profiles for diffractive optical devices made from absorbing materials", Appl. Opt. 21(17), 3209-3212W (1982). CrossRef W. B. Veldkamp, and C. J. Kastner, "Beam profile shaping for laser radars that use detector arrays", Appl. Opt. 21(2), 345-356 (1982). CrossRef https://www.mcortechnologies.com/de/3d-drucker/mcor-iris/ DirectLinkM. Sypek, M. Makowski, E. Hérault, A. Siemion, A. Siemion, J. Suszek, F. Garet, and J.-L. Coutaz, "Highly efficient broadband double-sided Fresnel lens for THz range", Opt. Lett. 37, 12 (2012). CrossRef

scholarly journals An approach to realisation of a Radial Phase mask using 3-D printing in transparent PLA

2017 ◽  
Vol 16 (1) ◽  
pp. 22-29
Author(s):  
Simran Agarwal ◽  
Romuald Jolivot ◽  
Waleed S. Mohammed
Keyword(s):  
Iterative Algorithm ◽  
Processing Time ◽  
Optical Element ◽  
Beam Shaping ◽  
Beam Profile ◽  
Phase Mask ◽  
Experimental Setup ◽  
Diffractive Optical Elements ◽  
Optical Elements ◽  
Radial Phase

In the recent years, many different techniques and algorithms have been devised to design diffractive optical elements (DOE’s) for the purpose of beam shaping. This paper demonstrates an approach to realise a 3-D printed radial phase mask to be used in beam shaping to achieve a beam profile closer to the flattop. An iterative algorithm approach is employed to simulate the phase masks in greyscale and subsequently into STL format. These 3-D printed masks are used as an optical element and characterised using an experimental setup. The images of the light after the characterisation are examined and compared with the simulated results. Therefore, this method reduces the complexity as 3-D printing the masks eliminates the need for fabrication, processing time and number of components necessary to obtain a flattop beam profile.

scholarly journals Chocolate Terahertz Fresnel Lens

2020 ◽  
Vol 12 (4) ◽  
pp. 103
Author(s):  
Mateusz Surma ◽  
Paweł Komorowski ◽  
Maciej Neneman ◽  
Agnieszka Siemion
Keyword(s):  
Terahertz Spectroscopy ◽  
Complex Refractive Index ◽  
Optical Element ◽  
Far Infrared ◽  
Computational Design ◽  
Fresnel Lens ◽  
Polymer Materials ◽  
Terahertz Waves ◽  
International Conference ◽  
3D Printed

Recent enormous development of 3D printing techniques gave the possibility of precise manufacturing of designed optical structures. This paper presents designing, manufacturing and the results obtained for chocolate Fresnel lens. Chocolate, similarly to wax, can be melted and used in the 3D printed form to create a terahertz (THz) optical element. Parameters of the chocolate lens are compared with the one made of wax. In simple applications both materials can be used as a cost-effective alternative for conventional optical materials used for THz range of radiation. Both lenses have been designed and compared for 140 GHz. Full Text: PDF ReferencesM. Naftaly, R.E. Miles, and P.J. Greenslade, "THz transmission in polymer materials — a data library", Joint 32nd International Conference on Infrared and Millimeter Waves and the 15th International Conference on Terahertz Electronics, 819-820 (2007). CrossRef S. Firoozabadi, F. Beltran-Mejia, A. Soltani, D. Jahn, S.F. Busch, J.C. Balzer, and M. Koch, "THz transmission blazed grating made out of paper tissue", 42nd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 1-2 (2017). CrossRef D. Headland, W. Withayachumnankul, M. Webb, H. Ebendorff-Heidepriem, A. Luiten, and D. Abbott, "Analysis of 3D-printed metal for rapid-prototyped reflective terahertz optics", Optics express 24(15), 17384-17396 (2016). CrossRef S.F. Busch, M. Weidenbach, M. Fey, F. Schäfer, T. Probst, and M. Koch, "Optical Properties of 3D Printable Plastics in the THz Regime and their Application for 3D Printed THz Optics", Journal of Infrared, Millimeter, and Terahertz Waves 35(12), 993-997 (2014). CrossRef C. Jördens, and M. Koch, "Detection of foreign bodies in chocolate with pulsed terahertz spectroscopy", Optical Engineering 47(3), 037003 (2008). CrossRef A.D. Squires, E. Constable, and R.A. Lewis, "3D Printed Terahertz Diffraction Gratings And Lenses", Journal of Infrared, Millimeter, and Terahertz Waves 36(1), 72-80 (2015). CrossRef W. D. Furlan, V. Ferrando, J. A. Monsoriu, P. Zagrajek, E. Czerwińska, and M. Szustakowski, "3D printed diffractive terahertz lenses", Optics letters 41(8), 1748-1751 (2016). CrossRef X. Wei, C. Liu, L. Niu, Z. Zhang, K. Wang, Z. Yang, and J. Liu, "Generation of arbitrary order Bessel beams via 3D printed axicons at the terahertz frequency range", Applied optics 54(36), 10641-10649 (2015). CrossRef S. Banerji, and B. Sensale-Rodriguez, "3D-printed diffractive terahertz optical elements through computational design", Micro-and Nanotechnology Sensors, Systems, and Applications XI 10982, 109822X, International Society for Optics and Photonics (2019). CrossRef M. Surma, I. Ducin, P. Zagrajek, and A. Siemion, "Sub-Terahertz Computer Generated Hologram with Two Image Planes", Applied Sciences 9(4), 659 (2019). CrossRef A. Siemion, P. Komorowski, M. Surma, I. Ducin, P. Sobotka, M. Walczakowski, and E. Czerwińska, "Terahertz diffractive structures for compact in-reflection inspection setup", Optics Express 28(1), 715-723 (2020). CrossRef E.R. Brown, J.E. Bjarnason, A.M. Fedor, and T.M. Korter, "On the strong and narrow absorption signature in lactose at 0.53THz", Applied Physics Letters 90(6), 061908 (2007). CrossRef M. Bernier, F. Garet, and J. L. Coutaz, "Determining the Complex Refractive Index of Materials in the Far-Infrared from Terahertz Time-Domain Data", Terahertz Spectroscopy-Cutting Edge Technology, Intech-Open Science (2017). CrossRef E.Hecht, Optics 5th global ed.(Boston, Pearson Education 2017). DirectLink

scholarly journals Computer synthesis of diffractive optical elements for forming 3D images

2017 ◽  
pp. 11-19
Author(s):  
С.Р. Дурлевич
Keyword(s):  
Optical Element ◽  
Diffractive Optical Element ◽  
Diffractive Optical Elements ◽  
Optimal Parameters ◽  
Optical Elements ◽  
Standard Equipment ◽  
3D Images ◽  
Security Feature ◽  
Diffractive Element ◽  
Visual Security

Предложен метод расчета и синтеза микрорельефа дифракционного оптического элемента, формирующего новый визуальный защитный признак - эффект смены одного 3D-изображения на другое 3D-изображение при повороте дифракционного оптического элемента на 90 градусов. Разработаны эффективные алгоритмы расчета микрорельефа дифракционного оптического элемента. Методами математического моделирования определены оптимальные параметры дифракционного оптического элемента. С помощью электронно-лучевой технологии изготовлены образцы оптических защитных элементов, формирующих визуальный эффект смены 3D-изображений при освещении оптического элемента белым светом. Разработанные оптические элементы могут тиражироваться с помощью стандартного оборудования, используемого для изготовления защитных голограмм. Новый защитный признак легко контролируется визуально, надежно защищен от подделки и предназначен для защиты банкнот, документов, идентификационных карт и др. A method is proposed to compute and synthesize the microrelief of a diffractive optical element to produce a new visual security feature: alternation of two 3D color images when the diffractive element is rotated by 90 degrees. Effective algorithms for computing the micro-relief of an optical element are developed. Optimal parameters of the diffractive optical element are determined using methods of mathematical modeling. Sample optical security elements that produce 3D to 3D visual switch effect when illuminated by white light were manufactured using the electron-beam lithography. The optical elements developed can be replicated using a standard equipment employed for manufacturing security holograms. The new optical security feature is easy to control visually, safely protected against counterfeit, and designed to protect banknotes, documents, ID cards, etc.

Design and Analysis of Flat-Top Beam Produced by Diffractive Optical Element

2015 ◽  
Vol 743 ◽  
pp. 800-807 ◽  
Author(s):  
S.Z. Nie ◽  
J. Yu ◽  
Y. Liu ◽  
Z.W. Fan
Keyword(s):  
Optical Element ◽  
Weighting Factor ◽  
Diffractive Optical Elements ◽  
Optical Elements ◽  
Empirical Constant ◽  
Modified Method ◽  
Input And Output ◽  
Diffractive Efficiency ◽  
The Relationship ◽  
Flat Top Beam

The modified Gerchberg-Saxton (G-S) methods of diffractive optical elements are presented for converting a Gaussian beam into a flat-top beam. The sample points of the input and output planes are discussed based on the sampling principle. The relationship between weighting factor, empirical constant, diffractive efficiency, and intensity uniformity is investigated. The simulation results of different modified methods are calculated when the incident beams are the same. The results show that the intensity uniformity of the output flat-top beam is the best when using the ST modified method.

scholarly journals Three-focal-spot terahertz diffractive optical element-iterative design and neural network approach

2021 ◽  
Vol 29 (7) ◽  
pp. 11243
Author(s):  
Paweł Komorowski ◽  
Patrycja Czerwińska ◽  
Mateusz Surma ◽  
Przemysław Zagrajek ◽  
Ryszard Piramidowicz ◽  
...  
Keyword(s):  
Neural Network ◽  
Focal Spot ◽  
Optical Element ◽  
Diffractive Optical Element ◽  
Network Approach ◽  
Neural Network Approach ◽  
Iterative Design
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