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Komorowski P, Czerwińska P, Surma M, Zagrajek P, Piramidowicz R, Siemion A. Three-focal-spot terahertz diffractive optical element-iterative design and neural network approach. Opt Express 2021; 29:11243-11253. [PMID: 33820240 DOI: 10.1364/oe.418059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
The redistribution of an incoming radiation into several beams is necessary in telecommunication to demultiplex data signals. In the terahertz spectral range, it can be realized by easy-to-manufacture diffractive optical elements (DOEs) allowing to focus the radiation into multiple focal spots in a single plane. In this article, we present diffractive optical elements focusing THz radiation into three focal spots. Different focal spot distributions (symmetric and asymmetric) are designed using an iterative algorithm. The phase distribution forming asymmetric focal spots can be realized by iterative design, which is a novel approach, to our knowledge. Then, the structures are manufactured using a sintering-based 3D-printing method from polyamide 12 (PA 12) and measured in an experimental setup for 150 GHz frequency. A novel approach based on neural networks (NNs) is proposed to optimize the phase delay maps of the structures to further improve their performance - the higher efficiency and the lower unwanted background noise.
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2
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Zeranska-Chudek K, Siemion A, Palka N, Mdarhri A, Elaboudi I, Brosseau C, Zdrojek M. Terahertz Shielding Properties of Carbon Black Based Polymer Nanocomposites. Materials (Basel) 2021; 14:835. [PMID: 33572422 PMCID: PMC7916217 DOI: 10.3390/ma14040835] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 01/28/2021] [Accepted: 02/04/2021] [Indexed: 11/18/2022]
Abstract
The majority of industry using high-speed communication systems is shifting towards higher frequencies, namely the terahertz range, to meet demands of more effective data transfer. Due to the rising number of devices working in terahertz range, effective shielding of electromagnetic interference (EMI) is required, and thus the need for novel shielding materials to reduce the electromagnetic pollution. Here, we show a study on optical and electrical properties of a series of ethylene co-butyl acrylate/carbon black (EBA/CB) composites with various CB loading. We investigate the transmittance, reflectance, shielding efficiency, absorption coefficient, refractive index and complex dielectric permittivity of the fabricated composites. Finally, we report a material that exhibits superior shielding efficiency (SE)-80 dB at 0.9 THz (14.44 vol% CB loading, 1 mm thick)-which is one of the highest SE values among non-metallic composite materials reported in the literature thus far. Importantly, 99% of the incoming radiation is absorbed by the material, significantly increasing its applicability. The absorption coefficient (α) reaches ~100 cm-1 for the samples with highest CB loading. The EBA/CB composites can be used as lightweight and flexible shielding packaging materials for electronics, as passive terahertz absorbers or as radiation shields for stealth applications.
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Affiliation(s)
- Klaudia Zeranska-Chudek
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00–662 Warsaw, Poland; (A.S.); (M.Z.)
| | - Agnieszka Siemion
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00–662 Warsaw, Poland; (A.S.); (M.Z.)
| | - Norbert Palka
- Institute of Optoelectronics, Military University of Technology, Kaliskiego 2, 00–908 Warsaw, Poland;
| | - Ahmed Mdarhri
- Laboratory of Sustainable Development and Health Research, Faculty of Sciences & Techniques Cadi Ayyad University, A. Khattabi BP 549, 40 000 Marrakesh, Morocco; (A.M.); (I.E.)
| | - Ilham Elaboudi
- Laboratory of Sustainable Development and Health Research, Faculty of Sciences & Techniques Cadi Ayyad University, A. Khattabi BP 549, 40 000 Marrakesh, Morocco; (A.M.); (I.E.)
| | - Christian Brosseau
- Lab-STICC, French National Center for Scientific Research, University of Brest, 6 Avenue Le Gorgeu, CEDEX 3, 29238 Brest, France;
| | - Mariusz Zdrojek
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00–662 Warsaw, Poland; (A.S.); (M.Z.)
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Siemion A. The Magic of Optics-An Overview of Recent Advanced Terahertz Diffractive Optical Elements. Sensors (Basel) 2020; 21:s21010100. [PMID: 33375221 PMCID: PMC7795556 DOI: 10.3390/s21010100] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/17/2020] [Accepted: 12/22/2020] [Indexed: 02/05/2023]
Abstract
Diffractive optical elements are well known for being not only flat but also lightweight, and are characterised by low attenuation. In different spectral ranges, they provide better efficiency than commonly used refractive lenses. An overview of the recently invented terahertz optical structures based on diffraction design is presented. The basic concepts of structure design together with various functioning of such elements are described. The methods for structure optimization are analysed and the new approach of using neural network is shown. The paper illustrates the variety of structures created by diffractive design and highlights optimization methods. Each structure has a particular complex transmittance that corresponds to the designed phase map. This precise control over the incident radiation phase changes is limited to the design wavelength. However, there are many ways to overcome this inconvenience allowing for broadband functioning.
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Affiliation(s)
- Agnieszka Siemion
- Faculty of Physics, Warsaw University of Technology, 75 Koszykowa, 00-662 Warsaw, Poland
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Zeranska‐Chudek K, Lapinska A, Siemion A, Jastrzębska AM, Zdrojek M. Terahertz time domain spectroscopy of graphene and
MXene
polymer composites. J Appl Polym Sci 2020. [DOI: 10.1002/app.49962] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
| | - Anna Lapinska
- Faculty of Physics Warsaw University of Technology Warsaw Poland
| | | | | | - Mariusz Zdrojek
- Faculty of Physics Warsaw University of Technology Warsaw Poland
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Deuter V, Grochowicz M, Brose S, Biller J, Danylyuk S, Taubner T, Siemion A, Grützmacher D, Juschkin L. Computational proximity lithography with extreme ultraviolet radiation. Opt Express 2020; 28:27000-27012. [PMID: 32906962 DOI: 10.1364/oe.398805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/18/2020] [Indexed: 06/11/2023]
Abstract
The potential of extreme ultraviolet (EUV) computational proximity lithography for fabrication of arbitrary nanoscale patterns is investigated. We propose to use a holographic mask (attenuating phase shifting mask) consisting of structures of two phase levels. This approach allows printing of arbitrary, non-periodic structures without using high-resolution imaging optics. The holographic mask is designed for a wavelength of 13.5 nm with a conventional high-resolution electron beam resist as the phase shifting medium (pixel size 50 nm). The imaging performance is evaluated by using EUV radiation with different degrees of spatial coherence. Therefore exposures on identical masks are carried out with both undulator radiation at a synchrotron facility and plasma-based radiation at a laboratory setup.
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Siemion A, Komorowski P, Surma M, Ducin I, Sobotka P, Walczakowski M, Czerwińska E. Terahertz diffractive structures for compact in-reflection inspection setup. Opt Express 2020; 28:715-723. [PMID: 32118994 DOI: 10.1364/oe.382272] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 12/20/2019] [Indexed: 06/10/2023]
Abstract
Two diffractive optical elements are used to create a compact raster THz scanning setup in reflective configuration. The first one focuses the radiation into the small focal spot on the sample, while the second one collects reflected radiation and focuses it on the detector. To assure small size of the setup and large apertures of optical elements, structures work in the off-axis geometry. Thus, the focal spot is formed 100 mm after and 60 mm below the optical axis of the element, which measures 75 mm in diameter. The designed iterative algorithm allows further minimization of these values.
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Kozanecka-Szmigiel A, Antonowicz J, Szmigiel D, Makowski M, Siemion A, Konieczkowska J, Trzebicka B, Schab-Balcerzak E. On stress – strain responses and photoinduced properties of some azo polymers. POLYMER 2018. [DOI: 10.1016/j.polymer.2018.02.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Siemion A, Sypek M, Suszek J, Makowski M, Siemion A, Kolodziejczyk A, Jaroszewicz Z. Diffuserless holographic projection working on twin spatial light modulators. Opt Lett 2012; 37:5064-6. [PMID: 23258006 DOI: 10.1364/ol.37.005064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
An improved efficient projection of holographic images is presented. It uses two phase spatial light modulators (SLMs) with two iteratively optimized Fresnel holograms displayed simultaneously--each for one modulator. The phase distribution on the second modulator is taking into account the light distribution coming from the first one. A pixelated structure of the modulator and fluctuations of liquid-crystal molecules cause a zero-order peak that was separated in experiment. Use of two SLMs gives clear and containing almost no speckles images. Thanks to the compensation of phase distribution from the first modulator, we can abandon diffusers in the iterative process and that is why we can control both amplitude and phase distribution in the image plane independently.
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Affiliation(s)
- Andrzej Siemion
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, Warsaw 00-662, Poland.
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Siemion A, Siemion A, Makowski M, Suszek J, Bomba J, Czerwiński A, Garet F, Coutaz JL, Sypek M. Diffractive paper lens for terahertz optics. Opt Lett 2012; 37:4320-4322. [PMID: 23073449 DOI: 10.1364/ol.37.004320] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Passive terahertz (THz) setups require optical elements with large diameters for optimal harvesting of weak signals. High f-number implies sophisticated aspheric designs to ensure optimal resolution and good energetic efficiency. Trial and error testing of such optics is expensive and numerical modeling is time consuming; hence, we propose extremely cheap diffractive lenses for THz made of regular paper. They are easy to manufacture even with large diameters, and the optical function can be easily customized, which can be used for initial experimental testing of THz setups. Characterization of the proposed diffractive lenses with time-domain spectroscopy is presented and discussed.
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Affiliation(s)
- Agnieszka Siemion
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, Warsaw 00 662, Poland
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Sypek M, Makowski M, Hérault E, Siemion A, Siemion A, Suszek J, Garet F, Coutaz JL. Highly efficient broadband double-sided Fresnel lens for THz range. Opt Lett 2012; 37:2214-2216. [PMID: 22739859 DOI: 10.1364/ol.37.002214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Modern passive THz setups require effective optical elements with a large numerical aperture. Here we propose a new type of the optical element for THz applications, which is a broadband double-sided Fresnel-like lens with an optimized thickness. The optimization is performed to obtain a very low attenuation, low material cost, and small weight in the element media. It also provides achromatic properties for the assumed wavelength range. The experimental evaluation of the proposed diffractive lens by means of time-domain spectroscopy is presented and discussed.
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Affiliation(s)
- Maciej Sypek
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00 662 Warsaw, Poland
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Makowski M, Ducin I, Kakarenko K, Kolodziejczyk A, Siemion A, Siemion A, Suszek J, Sypek M, Wojnowski D. Efficient image projection by Fourier electroholography. Opt Lett 2011; 36:3018-3020. [PMID: 21847145 DOI: 10.1364/ol.36.003018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
An improved efficient projection of color images is presented. It uses a phase spatial light modulator with three iteratively optimized Fourier holograms displayed simultaneously--each for one primary color. This spatial division instead of time division provides stable images. A pixelated structure of the modulator and fluctuations of liquid crystal molecules cause a zeroth-order peak, eliminated by additional wavelength-dependent phase factors shifting it before the image plane, where it is blocked with a matched filter. Speckles are suppressed by time integration of variable speckle patterns generated by additional randomizations of an initial phase and minor changes of the signal.
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Affiliation(s)
- Michał Makowski
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00 662 Warsaw, Poland.
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Siemion A, Siemion A, Makowski M, Sypek M, Hérault E, Garet F, Coutaz JL. Off-axis metallic diffractive lens for terahertz beams. Opt Lett 2011; 36:1960-1962. [PMID: 21633415 DOI: 10.1364/ol.36.001960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A diffractive optical element for off-axis focusing of terahertz radiation is presented. It was designed in a nonparaxial regime and manufactured in a metal slab by laser cutting of curved stripes. The optical function of the structure includes focusing and deflecting the illuminating beam of a chosen frequency in a particular place. Therefore, the element acts as both a spatial and a spectral filter; hence it is especially suitable for separating the terahertz signal from a broadband thermal load in passive detection devices. The experimental evaluation of the proposed diffractive lens by means of time-domain spectroscopy is presented and discussed.
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Affiliation(s)
- Agnieszka Siemion
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00 662 Warsaw, Poland
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13
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Makowski M, Ducin I, Sypek M, Siemion A, Siemion A, Suszek J, Kolodziejczyk A. Color image projection based on Fourier holograms. Opt Lett 2010; 35:1227-9. [PMID: 20410975 DOI: 10.1364/ol.35.001227] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A method of color image projection is experimentally validated. It assumes a simultaneous illumination of a spatial light modulator (SLM) with three laser beams converging in a common point on a projection screen. The beams are masked with amplitude filters so that each one illuminates one third of the area of the SLM. A Fourier hologram of a chosen color component of an input image is calculated, and its phase pattern is addressed on a corresponding part of the SLM area. A full-color flat image is formed on the screen as a result of color mixing. Additional techniques of image optimization are applied: time-integral speckle averaging and an off-axis shift of a zero-order peak. Static and animated experimental results of such a color holographic projection with a good image quality are presented.
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Affiliation(s)
- Michal Makowski
- Faculty of Physics, Warsaw University of Technology, 75 Koszykowa, 00-662 Warsaw, Poland.
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