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 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

Far-Infrared Fresnel Lens for Thermal Imaging

2013 ◽  
Vol 133 (7) ◽  
pp. 274-279
Author(s):  
Tomoyuki Takahata ◽  
Kiyoshi Matsumoto ◽  
Isao Shimoyama
Keyword(s):  
Thermal Imaging ◽  
Far Infrared ◽  
Fresnel Lens

scholarly journals Broadband spectroscopy of astrophysical ice analogues

2019 ◽  
Vol 629 ◽  
pp. A112 ◽  
Author(s):  
B. M. Giuliano ◽  
A. A. Gavdush ◽  
B. Müller ◽  
K. I. Zaytsev ◽  
T. Grassi ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Time Domain ◽  
Complex Refractive Index ◽  
Far Infrared ◽  
Infrared Region ◽  
Thz Radiation ◽  
The Real ◽  
Thz Range ◽  
The Time Domain

Context. Reliable, directly measured optical properties of astrophysical ice analogues in the infrared and terahertz (THz) range are missing from the literature. These parameters are of great importance to model the dust continuum radiative transfer in dense and cold regions, where thick ice mantles are present, and are necessary for the interpretation of future observations planned in the far-infrared region. Aims. Coherent THz radiation allows for direct measurement of the complex dielectric function (refractive index) of astrophysically relevant ice species in the THz range. Methods. We recorded the time-domain waveforms and the frequency-domain spectra of reference samples of CO ice, deposited at a temperature of 28.5 K and annealed to 33 K at different thicknesses. We developed a new algorithm to reconstruct the real and imaginary parts of the refractive index from the time-domain THz data. Results. The complex refractive index in the wavelength range 1 mm–150 μm (0.3–2.0 THz) was determined for the studied ice samples, and this index was compared with available data found in the literature. Conclusions. The developed algorithm of reconstructing the real and imaginary parts of the refractive index from the time-domain THz data enables us, for the first time, to determine the optical properties of astrophysical ice analogues without using the Kramers–Kronig relations. The obtained data provide a benchmark to interpret the observational data from current ground-based facilities as well as future space telescope missions, and we used these data to estimate the opacities of the dust grains in presence of CO ice mantles.

scholarly journals Optical Performance of Single Point-Focus Fresnel Lens Concentrator System for Multiple Multi-Junction Solar Cells—A Numerical Study

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4301
Author(s):  
Yassir A. Alamri ◽  
Saad Mahmoud ◽  
Raya Al-Dadah ◽  
Shivangi Sharma ◽  
J. N. Roy ◽  
...  
Keyword(s):  
Solar Cells ◽  
Numerical Study ◽  
Single Point ◽  
Optical Element ◽  
Fresnel Lens ◽  
Electrical Performance ◽  
High Concentration ◽  
Three Dimensional Model ◽  
Optical Efficiency ◽  
Concave Lens

This paper investigates the potential of a new integrated solar concentrated photovoltaic (CPV) system that uses a solo point focus Fresnel lens for multiple multi-junction solar cells (MJSCs). The proposed system comprises of an FL concentrator as the primary optical element, a multi-leg homogeniser as the secondary optical element (SOE), a plano-concave lens, and four MJSCs. A three-dimensional model of this system was developed using the ray tracing method to predict the influence of aperture width, height, and position with respect to MJSCs of different reflective and refractive SOE on the overall optical efficiency of the system and the irradiance uniformity achieved on the MJSCs’ surfaces. The results show that the refractive homogeniser using N-BK7 glass can achieve higher optical efficiency (79%) compared to the reflective homogeniser (57.5%). In addition, the peak to average ratio of illumination at MJSCs for the reflective homogeniser ranges from 1.07 to 1.14, while for the refractive homogeniser, it ranges from 1.06 to 1.34, causing minimum effects on the electrical performance of the MJSCs. The novelty of this paper is the development of a high concentration CPV system that integrates multiple MJSCs with a uniform distribution of rays, unlike the conventional CPV systems that utilise a single concentrator onto a single MJSC. The optical efficiency of the CPV system was also examined using both the types of homogeniser (reflective and refractive).

scholarly journals Off-Axis Diffractive Optics for Compact Terahertz Detection Setup

2020 ◽  
Vol 10 (23) ◽  
pp. 8594
Author(s):  
Paweł Komorowski ◽  
Mateusz Surma ◽  
Michał Walczakowski ◽  
Przemysław Zagrajek ◽  
Agnieszka Siemion
Keyword(s):  
3D Printing ◽  
Small Volume ◽  
Optical Element ◽  
Structure Design ◽  
Thz Radiation ◽  
Direct Printing ◽  
Terahertz Detection ◽  
3D Printed ◽  
Printing Techniques ◽  
Optical Structure

Medical and many other applications require small-volume setups enabling terahertz imaging. Therefore, we aim to develop a device for the in-reflection examination of the samples. Thus, in this article, we focus on the diffractive elements for efficient redirection and focusing of the THz radiation. A terahertz diffractive optical structure has been designed, optimized, manufactured (using extrusion-based 3D printing) and tested. Two manufacturing methods have been used—direct printing of the structures from PA12, and casting of the paraffin structures out of 3D-printed molds. Also, the limitations of the off-axis focusing have been discussed. To increase the efficiency, an iterative algorithm has been proposed that optimizes off-axis structures to focus the radiation into small focal spots located far from the optical axis, at an angle of more than 30 degrees. Moreover, the application of higher-order kinoform structure design allowed the maintaining of the smallest details of the manufactured optical element, using 3D printing techniques.

scholarly journals Bone-inspired 3D printed structures for construction applications

2019 ◽  
Vol 14 (1) ◽  
pp. 111-124
Author(s):  
Roberto Naboni ◽  
Anja Kunic
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Computational Design ◽  
Bone Microstructure ◽  
Manufacturing Technology ◽  
Support Design ◽  
Efficient Construction ◽  
3D Printed ◽  
Viable Approach ◽  
Tectonic System

Overconsumption of resources is one of the greatest challenges of our century. The amount of material that is being extracted, harvested and consumed in the last decades is increasing tremendously. Building with new manufacturing technology, such as 3D Printing, is offering new perspectives in the way material is utilized sustainably within a construction. This paper describes a study on how to use Additive Manufacturing to support design logics inspired by the bone microstructure, in order to build materially efficient architecture. A process which entangles computational design methods, testing of 3D printed specimens, developments of prototypes is described. A cellular-based tectonic system with the capacity to vary and adapt to different loading conditions is presented as a viable approach to a material-efficient construction with Additive Manufacturing.

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