{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T05:05:16Z","timestamp":1787029516140,"version":"3.56.0"},"reference-count":116,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2020,12,26]],"date-time":"2020-12-26T00:00:00Z","timestamp":1608940800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100005632","name":"Narodowe Centrum Bada\u0144 i Rozwoju","doi-asserted-by":"publisher","award":["LIDER \/11\/0036 \/ L-9\/17 \/ NCBR \/ 2018"],"award-info":[{"award-number":["LIDER \/11\/0036 \/ L-9\/17 \/ NCBR \/ 2018"]}],"id":[{"id":"10.13039\/501100005632","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>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.<\/jats:p>","DOI":"10.3390\/s21010100","type":"journal-article","created":{"date-parts":[[2020,12,27]],"date-time":"2020-12-27T20:52:21Z","timestamp":1609102341000},"page":"100","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":55,"title":["The Magic of Optics\u2014An Overview of Recent Advanced Terahertz Diffractive Optical Elements"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2020-6842","authenticated-orcid":false,"given":"Agnieszka","family":"Siemion","sequence":"first","affiliation":[{"name":"Faculty of Physics, Warsaw University of Technology, 75 Koszykowa, 00-662 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,12,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"4320","DOI":"10.1364\/OL.37.004320","article-title":"Diffractive paper lens for terahertz optics","volume":"37","author":"Siemion","year":"2012","journal-title":"Opt. Lett."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Rachon, M., Liebert, K., But, D., Zagrajek, P., Siemion, A., Kolodziejczyk, A., Sypek, M., and Suszek, J. (2020). Enhanced Sub-wavelength Focusing by Double-Sided Lens with Phase Correction in THz Range. J. Infrared Millim. Terahertz Waves.","DOI":"10.1007\/s10762-020-00696-0"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1875","DOI":"10.1364\/OL.42.001875","article-title":"Terahertz multilevel phase Fresnel lenses fabricated by laser patterning of silicon","volume":"42","author":"Voisiat","year":"2017","journal-title":"Opt. Lett."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1007\/s10762-015-0236-7","article-title":"THz optics 3D printed with TOPAS","volume":"37","author":"Busch","year":"2016","journal-title":"J. Infrared Millim. Terahertz Waves"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1019","DOI":"10.1007\/s10762-017-0398-6","article-title":"THz beam shaper realizing fan-out patterns","volume":"38","author":"Liebert","year":"2017","journal-title":"J. Infrared Millim. Terahertz Waves"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"715","DOI":"10.1364\/OE.382272","article-title":"Terahertz diffractive structures for compact in-reflection inspection setup","volume":"28","author":"Siemion","year":"2020","journal-title":"Opt. Express"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/TASC.2019.2896153","article-title":"Josephson Cantilevers for THz Microscopy of Additive Manufactured Diffractive Optical Components","volume":"29","author":"Hampel","year":"2019","journal-title":"IEEE Trans. Appl. Supercond."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Firoozabadi, S., Beltran-Mejia, F., Soltani, A., Jahn, D., Busch, S., Balzer, J., and Koch, M. (September, January 27). THz transmission blazed grating made out of paper tissue. Proceedings of the 2017 42nd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), Cancun, Mexico.","DOI":"10.1109\/IRMMW-THz.2017.8066945"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"568","DOI":"10.1109\/TTHZ.2016.2575440","article-title":"THz beam shaping based on paper diffractive optics","volume":"6","author":"Siemion","year":"2016","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Surma, M., Ducin, I., Zagrajek, P., and Siemion, A. (2019). Sub-Terahertz Computer Generated Hologram with Two Image Planes. Appl. Sci., 9.","DOI":"10.3390\/app9040659"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"221104","DOI":"10.1063\/1.5027179","article-title":"3D-printed phase waveplates for THz beam shaping","volume":"112","author":"Gospodaric","year":"2018","journal-title":"Appl. Phys. Lett."},{"key":"ref_12","first-page":"1","article-title":"Terahertz circular Airy vortex beams","volume":"7","author":"Liu","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1304","DOI":"10.1126\/science.1235399","article-title":"Terahertz metamaterials for linear polarization conversion and anomalous refraction","volume":"340","author":"Grady","year":"2013","journal-title":"Science"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"041109","DOI":"10.1063\/1.4816345","article-title":"Metamaterial-based gradient index beam steerers for terahertz radiation","volume":"103","author":"Neu","year":"2013","journal-title":"Appl. Phys. Lett."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"164","DOI":"10.1016\/j.optcom.2014.02.017","article-title":"Dispersion characteristic of ultrathin terahertz planar lenses based on metasurface","volume":"322","author":"Hu","year":"2014","journal-title":"Opt. Commun."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1019","DOI":"10.1021\/acsphotonics.6b00102","article-title":"Dielectric resonator reflectarray as high-efficiency nonuniform terahertz metasurface","volume":"3","author":"Headland","year":"2016","journal-title":"ACS Photonics"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1867","DOI":"10.1364\/OL.42.001867","article-title":"Demonstration of a highly efficient terahertz flat lens employing tri-layer metasurfaces","volume":"42","author":"Chang","year":"2017","journal-title":"Opt. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"14132","DOI":"10.1364\/OE.26.014132","article-title":"All-dielectric metalens for terahertz wave imaging","volume":"26","author":"Jiang","year":"2018","journal-title":"Opt. Express"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"051101","DOI":"10.1063\/1.5011063","article-title":"Tutorial: Terahertz beamforming, from concepts to realizations","volume":"3","author":"Headland","year":"2018","journal-title":"APL Photonics"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/JSTQE.2016.2640452","article-title":"Terahertz reflectarrays and nonuniform metasurfaces","volume":"23","author":"Headland","year":"2016","journal-title":"IEEE J. Sel. Top. Quantum Electron."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"477","DOI":"10.1007\/s10762-019-00581-5","article-title":"Terahertz Diffractive Optics\u2014Smart Control over Radiation","volume":"40","author":"Siemion","year":"2019","journal-title":"J. Infrared Millim. Terahertz Waves"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1109\/JQE.2005.858451","article-title":"Specialized electron beam nanolithography for EUV and X-ray diffractive optics","volume":"42","author":"Anderson","year":"2005","journal-title":"IEEE J. Quantum Electron."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"27000","DOI":"10.1364\/OE.398805","article-title":"Computational proximity lithography with extreme ultraviolet radiation","volume":"28","author":"Deuter","year":"2020","journal-title":"Opt. Express"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1117\/12.537195","article-title":"Design and fabrication of advanced EUV diffractive elements","volume":"Volume 5347","author":"Naulleau","year":"2003","journal-title":"Micromachining Technology for Micro-Optics and Nano-Optics II"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Braun, S., and Leson, A. (2015). Optical Elements for EUV Lithography and X-ray Optics. Nanoscale Multifunctional Materials, Wiley-VCH Verlag GmbH & Co. KGaA.","DOI":"10.1002\/9783527679195.ch30"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"344","DOI":"10.1038\/eye.1991.55","article-title":"Diffractive bifocal contact lenses in aphakia and pseudophakia","volume":"5","author":"Barton","year":"1991","journal-title":"Eye"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"446","DOI":"10.1016\/j.jcrs.2010.10.045","article-title":"Visual function and patient satisfaction: Comparison between bilateral diffractive multifocal intraocular lenses and monovision pseudophakia","volume":"37","author":"Zhang","year":"2011","journal-title":"J. Cataract Refract. Surg."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1515\/aot-2014-0008","article-title":"Transferring diffractive optics from research to commercial applications: Part II\u2013size estimations for selected markets","volume":"3","author":"Brunner","year":"2014","journal-title":"Adv. Opt. Technol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"385","DOI":"10.21300\/20.4.2019.385","article-title":"Inventing a New Way to See Clearly: Non-invasive Vision Correction with Femtosecond Lasers","volume":"20","author":"Knox","year":"2019","journal-title":"Technol. Innov."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"506","DOI":"10.1364\/AO.44.000506","article-title":"Design and fabrication of diffractive optical elements by use of gray-scale photolithography","volume":"44","author":"Sohn","year":"2005","journal-title":"Appl. Opt."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"2832","DOI":"10.1364\/AO.27.002832","article-title":"Antireflection coatings for germanium IR optics: A comparison of numerical design methods","volume":"27","author":"Aguilera","year":"1988","journal-title":"Appl. Opt."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"288","DOI":"10.1364\/AO.21.000288","article-title":"High performance step-down AR coatings for high refractive-index IR materials","volume":"21","author":"Dobrowolski","year":"1982","journal-title":"Appl. Opt."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Lee, Y.S. (2009). Principles of Terahertz Science and Technology, Springer Science & Business Media.","DOI":"10.1007\/978-0-387-09540-0_5"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"8670","DOI":"10.1364\/AO.52.008670","article-title":"Terahertz lens made out of natural stone","volume":"52","author":"Han","year":"2013","journal-title":"Appl. Opt."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"090505","DOI":"10.1117\/1.OE.55.9.090505","article-title":"Cast terahertz lenses made of caramelized sucrose","volume":"55","author":"Sterczewski","year":"2016","journal-title":"Opt. Eng."},{"key":"ref_36","first-page":"114990C","article-title":"Terahertz diffractive optics: Different way of thinking","volume":"Volume 11499","author":"Siemion","year":"2020","journal-title":"Terahertz Emitters, Receivers, and Applications XI"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"614","DOI":"10.1007\/s10762-018-0498-y","article-title":"Feasibility and characterization of common and exotic filaments for use in 3D printed terahertz devices","volume":"39","author":"Squires","year":"2018","journal-title":"J. Infrared Millim. Terahertz Waves"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"210901","DOI":"10.1063\/1.5140270","article-title":"Additive manufacture of photonic components for the terahertz band","volume":"127","author":"Koch","year":"2020","journal-title":"J. Appl. Phys."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"739","DOI":"10.1109\/2944.571775","article-title":"A reliable method for extraction of material parameters in terahertz time-domain spectroscopy","volume":"2","author":"Duvillaret","year":"1996","journal-title":"IEEE J. Sel. Top. Quantum Electron."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"409","DOI":"10.1364\/AO.38.000409","article-title":"Highly precise determination of optical constants and sample thickness in terahertz time-domain spectroscopy","volume":"38","author":"Duvillaret","year":"1999","journal-title":"Appl. Opt."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1562","DOI":"10.1364\/JOSAA.18.001562","article-title":"Material parameter estimation with terahertz time-domain spectroscopy","volume":"18","author":"Dorney","year":"2001","journal-title":"JOSA A"},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Siemion, A., Kostrowiecki-Lopata, P., Pindur, A., Zagrajek, P., and Sypek, M. (2016). Paper on designing costless THz paper optics. Adv. Mater. Sci. Eng., 2016.","DOI":"10.1155\/2016\/9615698"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"723","DOI":"10.1109\/JPROC.2016.2639520","article-title":"Investigation on 3-D-printing technologies for millimeter-wave and terahertz applications","volume":"105","author":"Zhang","year":"2017","journal-title":"Proc. IEEE"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"545","DOI":"10.1016\/j.promfg.2017.07.148","article-title":"The role of additive manufacturing in the era of industry 4.0","volume":"11","author":"Dilberoglu","year":"2017","journal-title":"Procedia Manuf."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"596","DOI":"10.1016\/j.memsci.2016.10.006","article-title":"Perspective on 3D printing of separation membranes and comparison to related unconventional fabrication techniques","volume":"523","author":"Low","year":"2017","journal-title":"J. Membr. Sci."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1007\/s10762-019-0568-9","article-title":"Metalized Poly-methacrylate Off-Axis Parabolic Mirrors for Terahertz Imaging Fabricated by Additive Manufacturing","volume":"40","author":"Fullager","year":"2019","journal-title":"J. Infrared Millim. Terahertz Waves"},{"key":"ref_47","first-page":"2780","article-title":"Multilevel silicon diffractive optics for terahertz waves","volume":"20","author":"Walsby","year":"2002","journal-title":"J. Vac. Sci. Technol. B Microelectron. Nanometer Struct. Process. Meas. Phenom."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"933","DOI":"10.1070\/QE2015v045n10ABEH015890","article-title":"Fabrication of a multilevel THz Fresnel lens by femtosecond laser ablation","volume":"45","author":"Komlenok","year":"2015","journal-title":"Quantum Electron."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"1210","DOI":"10.1364\/OL.44.001210","article-title":"Laser-processed diffractive lenses for the frequency range of 4.7 THz","volume":"44","author":"Richter","year":"2019","journal-title":"Opt. Lett."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"264","DOI":"10.1109\/75.856983","article-title":"An anti-reflection coating for silicon optics at terahertz frequencies","volume":"10","author":"Gatesman","year":"2000","journal-title":"IEEE Microw. Guid. Wave Lett."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"541","DOI":"10.1109\/TTHZ.2018.2859619","article-title":"Focusing of terahertz radiation with laser-ablated antireflective structures","volume":"8","author":"Urbanowicz","year":"2018","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1117\/12.17930","article-title":"Higher-order kinoforms","volume":"Volume 1211","author":"Marron","year":"1990","journal-title":"Computer and Optically Formed Holographic Optics"},{"key":"ref_53","doi-asserted-by":"crossref","unstructured":"Middendorf, J., LeMaster, D., Zarepoor, M., and Brown, E. (2012, January 23\u201328). Design of multi-order diffractive THz lenses. Proceedings of the 2012 37th International Conference on Infrared, Millimeter, and Terahertz Waves, Wollongong, Australia.","DOI":"10.1109\/IRMMW-THz.2012.6380211"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"3137","DOI":"10.1364\/OE.22.003137","article-title":"High order kinoforms as a broadband achromatic diffractive optics for terahertz beams","volume":"22","author":"Suszek","year":"2014","journal-title":"Opt. Express"},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"17384","DOI":"10.1364\/OE.24.017384","article-title":"Analysis of 3D-printed metal for rapid-prototyped reflective terahertz optics","volume":"24","author":"Headland","year":"2016","journal-title":"Opt. Express"},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"115","DOI":"10.4302\/plp.v10i4.873","article-title":"Optimization of THz diffractive optical elements thickness","volume":"10","author":"Surma","year":"2018","journal-title":"Photonics Lett. Pol."},{"key":"ref_57","unstructured":"Soifer, V.A., Kotlar, V., and Doskolovich, L. (1997). Iteractive Methods for Diffractive Optical Elements Computation, CRC Press."},{"key":"ref_58","doi-asserted-by":"crossref","unstructured":"O\u2019Shea, D.C., Suleski, T.J., Kathman, A.D., and Prather, D.W. (2004). Diffractive Optics: Design, Fabrication, and Test, SPIE Press.","DOI":"10.1117\/3.527861"},{"key":"ref_59","unstructured":"Goodman, J.W. (2005). Introduction to Fourier Optics, Roberts and Company Publishers."},{"key":"ref_60","doi-asserted-by":"crossref","unstructured":"Del Mar S\u00e1nchez-L\u00f3pez, M., Moreno, I., and Mart\u00ednez-Garc\u00eda, A. (2009). Teaching diffraction gratings by means of a phasor analysis. Education and Training in Optics and Photonics, Optical Society of America.","DOI":"10.1364\/ETOP.2009.EMA1"},{"key":"ref_61","doi-asserted-by":"crossref","unstructured":"Minin, I.V., and Minin, O.V. (2004). Diffractional Optics of Millimetre Waves, CRC Press.","DOI":"10.1201\/9781420034486"},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"961","DOI":"10.1364\/JOSAA.7.000961","article-title":"Diffractive optical elements: Iterative calculation of quantized, blazed phase structures","volume":"7","author":"Wyrowski","year":"1990","journal-title":"JOSA A"},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1016\/S0167-9317(97)00188-3","article-title":"Design and fabrication of diffractive optical elements","volume":"34","author":"Taghizadeh","year":"1997","journal-title":"Microelectron. Eng."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"1521","DOI":"10.1063\/1.1502192","article-title":"Effect on laser-ablation algorithms of reflection losses and nonnormal incidence on the anterior cornea","volume":"81","author":"Anera","year":"2002","journal-title":"Appl. Phys. Lett."},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"1464","DOI":"10.1364\/OL.38.001464","article-title":"Evaluation of the shadow effect in terahertz kinoform gratings","volume":"38","author":"Suszek","year":"2013","journal-title":"Opt. Lett."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"1341","DOI":"10.1364\/OSAC.1.001341","article-title":"Generation of a terahertz collimated top-hat beam by using two thin diffractive phase plates","volume":"1","author":"Ye","year":"2018","journal-title":"OSA Contin."},{"key":"ref_67","doi-asserted-by":"crossref","unstructured":"Ka\u0161alynas, I., Venckevi\u010dius, R., Minkevi\u010dius, L., Se\u0161ek, A., Wahaia, F., Tamo\u0161i\u016bnas, V., Voisiat, B., Seliuta, D., Valu\u0161is, G., and \u0160vigelj, A. (2016). Spectroscopic terahertz imaging at room temperature employing microbolometer terahertz sensors and its application to the study of carcinoma tissues. Sensors, 16.","DOI":"10.3390\/s16040432"},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"100910F","DOI":"10.1117\/12.2253634","article-title":"Laser processing for precise fabrication of the THz optics","volume":"Volume 10091","author":"Voisiat","year":"2017","journal-title":"Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XXII"},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"170","DOI":"10.1016\/j.phpro.2016.11.030","article-title":"Fabrication of high-effective silicon diffractive optics for the terahertz range by femtosecond laser ablation","volume":"84","author":"Pavelyev","year":"2016","journal-title":"Phys. Procedia"},{"key":"ref_70","doi-asserted-by":"crossref","unstructured":"Minkevi\u010dius, L., Indri\u0161i\u016bnas, S., \u0160niaukas, R., Ra\u010diukaitis, G., Janonis, V., Tamo\u0161i\u016bnas, V., Ka\u0161alynas, I., and Valu\u0161is, G. (2018). Compact diffractive optics for THz imaging. Lith. J. Phys., 58.","DOI":"10.3952\/physics.v58i1.3655"},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"105953","DOI":"10.1016\/j.optlastec.2019.105953","article-title":"Silicon kinoform cylindrical lens with low surface roughness for high-power terahertz radiation","volume":"123","author":"Kononenko","year":"2020","journal-title":"Opt. Laser Technol."},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"D88","DOI":"10.1364\/JOSAB.36.000D88","article-title":"Terahertz focusing properties of polymeric zone plates characterized by a modified knife-edge technique","volume":"36","author":"Tofani","year":"2019","journal-title":"JOSA B"},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"14725","DOI":"10.1364\/OE.27.014725","article-title":"Terahertz image reconstruction based on compressed sensing and inverse Fresnel diffraction","volume":"27","author":"Shang","year":"2019","journal-title":"Opt. Express"},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"347","DOI":"10.1007\/s10762-016-0342-1","article-title":"Geometrical aberration suppression for large aperture sub-THz lenses","volume":"38","author":"Rachon","year":"2017","journal-title":"J. Infrared Millim. Terahertz Waves"},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"140","DOI":"10.1109\/TTHZ.2017.2762292","article-title":"Terahertz sieves","volume":"8","author":"Machado","year":"2017","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"2000842","DOI":"10.1002\/adom.202000842","article-title":"Broadband Achromatic Sub-Diffraction Focusing by an Amplitude-Modulated Terahertz Metalens","volume":"8","author":"Zhao","year":"2020","journal-title":"Adv. Opt. Mater."},{"key":"ref_77","doi-asserted-by":"crossref","first-page":"124764","DOI":"10.1016\/j.optcom.2019.124764","article-title":"Subdiffraction focusing of total electric fields of terahertz wave","volume":"458","author":"Yang","year":"2020","journal-title":"Opt. Commun."},{"key":"ref_78","doi-asserted-by":"crossref","unstructured":"Iba, A., Domier, C.W., Ikeda, M., Mase, A., Pham, A.V., and Luhmann, N.C. (2019, January 1\u20136). Realizing sub-diffraction focusing for terahertz. Proceedings of the 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), Paris, France.","DOI":"10.1109\/IRMMW-THz.2019.8874196"},{"key":"ref_79","doi-asserted-by":"crossref","first-page":"1748","DOI":"10.1364\/OL.41.001748","article-title":"3D printed diffractive terahertz lenses","volume":"41","author":"Furlan","year":"2016","journal-title":"Opt. Lett."},{"key":"ref_80","doi-asserted-by":"crossref","first-page":"2795","DOI":"10.1364\/OL.43.002795","article-title":"Fibonacci terahertz imaging by silicon diffractive optics","volume":"43","author":"Jokubauskis","year":"2018","journal-title":"Opt. Lett."},{"key":"ref_81","doi-asserted-by":"crossref","first-page":"3400106","DOI":"10.1109\/JPHOT.2013.2248707","article-title":"Bifocal Fibonacci diffractive lenses","volume":"5","author":"Monsoriu","year":"2013","journal-title":"IEEE Photonics J."},{"key":"ref_82","doi-asserted-by":"crossref","first-page":"617","DOI":"10.1080\/09500349608232770","article-title":"Non-paraxial analytical solution for the generation of focal curves","volume":"43","author":"Jaroszewicz","year":"1996","journal-title":"J. Mod. Opt."},{"key":"ref_83","doi-asserted-by":"crossref","first-page":"20119","DOI":"10.1364\/OE.24.020119","article-title":"Terahertz 3D printed diffractive lens matrices for field-effect transistor detector focal plane arrays","volume":"24","author":"Szkudlarek","year":"2016","journal-title":"Opt. Express"},{"key":"ref_84","doi-asserted-by":"crossref","first-page":"76","DOI":"10.4302\/plp.v10i3.845","article-title":"THz diffractive focusing structures for broadband application","volume":"10","author":"Liebert","year":"2018","journal-title":"Photonics Lett. Pol."},{"key":"ref_85","first-page":"463","article-title":"Study of thin, achromatic diffractive structures to focus terahertz radiation on a detector","volume":"50","author":"Liebert","year":"2020","journal-title":"Opt. Appl."},{"key":"ref_86","doi-asserted-by":"crossref","first-page":"28800","DOI":"10.1038\/srep28800","article-title":"A broadband terahertz ultrathin multi-focus lens","volume":"6","author":"He","year":"2016","journal-title":"Sci. Rep."},{"key":"ref_87","doi-asserted-by":"crossref","first-page":"529","DOI":"10.1016\/j.carbon.2018.02.095","article-title":"The novel hybrid metal-graphene metasurfaces for broadband focusing and beam-steering in farfield at the terahertz frequencies","volume":"132","author":"Zhang","year":"2018","journal-title":"Carbon"},{"key":"ref_88","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/s41598-019-43852-w","article-title":"Unusual terahertz waveforms from a resonant medium controlled by diffractive optical elements","volume":"9","author":"Pakhomov","year":"2019","journal-title":"Sci. Rep."},{"key":"ref_89","doi-asserted-by":"crossref","first-page":"471","DOI":"10.1109\/TTHZ.2019.2926630","article-title":"Diffraction-free THz sheet and its application on THz imaging system","volume":"9","author":"Zhang","year":"2019","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_90","doi-asserted-by":"crossref","first-page":"1493","DOI":"10.1364\/OL.25.001493","article-title":"Alternative formulation for invariant optical fields: Mathieu beams","volume":"25","year":"2000","journal-title":"Opt. Lett."},{"key":"ref_91","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/S0030-4018(01)01415-8","article-title":"Composition of the angular spectrum of the pseudo-nondiffracting beams","volume":"197","author":"Bouchal","year":"2001","journal-title":"Opt. Commun."},{"key":"ref_92","doi-asserted-by":"crossref","first-page":"29342","DOI":"10.1364\/OE.24.029342","article-title":"3D-printed diffractive elements induced accelerating terahertz Airy beam","volume":"24","author":"Liu","year":"2016","journal-title":"Opt. Express"},{"key":"ref_93","unstructured":"Zhang, D., Chen, B., Ba, Z., Ni, S., Cao, J., and Wang, X. (April, January 31). Generation of Broadband THz Airy Beams Applying 3D Printing Technique. Proceedings of the 2019 13th European Conference on Antennas and Propagation (EuCAP), Krakow, Poland."},{"key":"ref_94","doi-asserted-by":"crossref","first-page":"36358","DOI":"10.1364\/OE.27.036358","article-title":"Bessel terahertz imaging with enhanced contrast realized by silicon multi-phase diffractive optics","volume":"27","author":"Jokubauskis","year":"2019","journal-title":"Opt. Express"},{"key":"ref_95","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/JPHOT.2018.2887139","article-title":"Diffractive elements for zero-order Bessel beam generation with application in the terahertz reflection imaging","volume":"11","author":"Niu","year":"2018","journal-title":"IEEE Photonics J."},{"key":"ref_96","doi-asserted-by":"crossref","unstructured":"Wu, G.B., Chan, K.F., and Chan, C.H. (2020). 3-D Printed Terahertz Lens to Generate Higher-Order Bessel Beams Carrying OAM. IEEE Transactions on Antennas and Propagation, IEEE.","DOI":"10.23919\/EuCAP48036.2020.9135723"},{"key":"ref_97","doi-asserted-by":"crossref","first-page":"023846","DOI":"10.1103\/PhysRevA.96.023846","article-title":"High-power Bessel beams with orbital angular momentum in the terahertz range","volume":"96","author":"Choporova","year":"2017","journal-title":"Phys. Rev. A"},{"key":"ref_98","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1007\/s11082-016-0496-z","article-title":"Fabrication and characterization of diffractive phase plates for forming high-power terahertz vortex beams using free electron laser radiation","volume":"48","author":"Volodkin","year":"2016","journal-title":"Opt. Quantum Electron."},{"key":"ref_99","doi-asserted-by":"crossref","first-page":"1417","DOI":"10.1364\/OE.380076","article-title":"Generating terahertz perfect optical vortex beams by diffractive elements","volume":"28","author":"Yang","year":"2020","journal-title":"Opt. Express"},{"key":"ref_100","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1109\/TTHZ.2018.2883831","article-title":"Multiplexing THz Vortex Beams With a Single Diffractive 3-D Printed Lens","volume":"9","author":"Machado","year":"2018","journal-title":"IEEE Trans. Terahertz Sci. Technol."},{"key":"ref_101","doi-asserted-by":"crossref","first-page":"12534","DOI":"10.1364\/OE.24.012534","article-title":"Discrimination of orbital angular momentum modes of the terahertz vortex beam using a diffractive mode transformer","volume":"24","author":"Liu","year":"2016","journal-title":"Opt. Express"},{"key":"ref_102","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1364\/AOP.7.000066","article-title":"Optical communications using orbital angular momentum beams","volume":"7","author":"Willner","year":"2015","journal-title":"Adv. Opt. Photonics"},{"key":"ref_103","doi-asserted-by":"crossref","first-page":"12732","DOI":"10.1364\/OE.27.012732","article-title":"Terahertz dispersion using multi-depth phase modulation grating","volume":"27","author":"Yang","year":"2019","journal-title":"Opt. Express"},{"key":"ref_104","doi-asserted-by":"crossref","first-page":"21737","DOI":"10.1364\/OE.399376","article-title":"Terahertz beam steering using active diffraction grating fabricated by 3D printing","volume":"28","author":"Seifert","year":"2020","journal-title":"Opt. Express"},{"key":"ref_105","doi-asserted-by":"crossref","first-page":"124203","DOI":"10.1088\/1674-1056\/26\/12\/124203","article-title":"High efficiency terahertz diffraction grating with trapezoidal elements","volume":"26","author":"Wu","year":"2017","journal-title":"Chin. Phys. B"},{"key":"ref_106","doi-asserted-by":"crossref","first-page":"6581","DOI":"10.1364\/OE.25.006581","article-title":"Efficiency of multi-beam Fourier phase gratings at 1.4 THz","volume":"25","author":"Mirzaei","year":"2017","journal-title":"Opt. Express"},{"key":"ref_107","doi-asserted-by":"crossref","first-page":"312","DOI":"10.1016\/0030-4018(71)90095-2","article-title":"High-efficiency in-line multiple imaging by means of multiple phase holograms","volume":"3","author":"Dammann","year":"1971","journal-title":"Opt. Commun."},{"key":"ref_108","doi-asserted-by":"crossref","first-page":"505","DOI":"10.1080\/713819570","article-title":"Coherent optical generation and inspection of two-dimensional periodic structures","volume":"24","author":"Dammann","year":"1977","journal-title":"Opt. Acta: Int. J. Opt."},{"key":"ref_109","doi-asserted-by":"crossref","first-page":"2384","DOI":"10.1364\/OL.43.002384","article-title":"Resonance-domain diffractive lens for the terahertz region","volume":"43","author":"Nadell","year":"2018","journal-title":"Opt. Lett."},{"key":"ref_110","doi-asserted-by":"crossref","unstructured":"Banerji, S., Chanana, A., Condori-Quispe, H.O., Arezoomandan, S., Nahata, A., and Sensale-Rodriguez, B. (September, January 29). Demonstration of computational THz diffractive optical elements enabled by a modified direct binary search technique. Proceedings of the 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), Chengdu, China.","DOI":"10.1109\/IRMMW-THz.2018.8510117"},{"key":"ref_111","first-page":"109822X","article-title":"3D-printed diffractive terahertz optical elements through computational design","volume":"Volume 10982","author":"Banerji","year":"2019","journal-title":"Micro-and Nanotechnology Sensors, Systems, and Applications XI"},{"key":"ref_112","doi-asserted-by":"crossref","unstructured":"Banerji, S., Chanana, A., Condori, H., Nahata, A., and Sensale-Rodriguez, B. (2018). Efficient Design of Diffractive THz Lenses for Aberration Rectified Focusing via Modified Binary Search Algorithm. CLEO: QELS_Fundamental Science, Optical Society of America.","DOI":"10.1364\/CLEO_AT.2018.JW2A.76"},{"key":"ref_113","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/s41598-019-42243-5","article-title":"A computational design framework for efficient, fabrication error-tolerant, planar THz diffractive optical elements","volume":"9","author":"Banerji","year":"2019","journal-title":"Sci. Rep."},{"key":"ref_114","doi-asserted-by":"crossref","first-page":"1004","DOI":"10.1126\/science.aat8084","article-title":"All-optical machine learning using diffractive deep neural networks","volume":"361","author":"Lin","year":"2018","journal-title":"Science"},{"key":"ref_115","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/s41377-019-0223-1","article-title":"Design of task-specific optical systems using broadband diffractive neural networks","volume":"8","author":"Luo","year":"2019","journal-title":"Light. Sci. Appl."},{"key":"ref_116","doi-asserted-by":"crossref","first-page":"2906","DOI":"10.1364\/OL.394046","article-title":"All-optical diffractive neural networked terahertz hologram","volume":"45","author":"Liao","year":"2020","journal-title":"Opt. Lett."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/1\/100\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:46:21Z","timestamp":1760179581000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/1\/100"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,12,26]]},"references-count":116,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2021,1]]}},"alternative-id":["s21010100"],"URL":"https:\/\/doi.org\/10.3390\/s21010100","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,12,26]]}}}