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Su C, Ding C, Yang Z, Cao C, Qiu Y, Zhu D, Kuang C, Liu X. Sub-diffraction optical beam lithography based on a center-non-zero depletion laser. OPTICS LETTERS 2024; 49:109-112. [PMID: 38134164 DOI: 10.1364/ol.504691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 11/12/2023] [Indexed: 12/24/2023]
Abstract
Photoinhibition (PI) mechanisms have been introduced in nanofabrication which allows breaking the diffraction limit by large factors. Donut-shaped laser is usually selected as a depletion beam to reduce linewidth, but the parasitic process has made the results of the experiment less than expected. As a result, the linewidth is difficult to achieve below 50 nm with 780 nm femtosecond and 532 nm continuous-wave lasers. Here, we propose a new, to the best of our knowledge, method based on a center-non-zero (CNZ) depletion laser to further reduce linewidth. By constructing a smaller zone of action under the condition of keeping the maximum depletion intensity constant, a minimum linewidth of 30 nm (λ / 26) was achieved. Two ways to construct CNZ spots were discussed and experimented, and the results show the advantages of our method to reduce the parasitic process to further improve the writing resolution.
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2
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Bauer J, Crook C, Baldacchini T. A sinterless, low-temperature route to 3D print nanoscale optical-grade glass. Science 2023; 380:960-966. [PMID: 37262172 DOI: 10.1126/science.abq3037] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 04/12/2023] [Indexed: 06/03/2023]
Abstract
Three-dimensional (3D) printing of silica glass is dominated by techniques that rely on traditional particle sintering. At the nanoscale, this limits their adoption within microsystem technology, which prevents technological breakthroughs. We introduce the sinterless, two-photon polymerization 3D printing of free-form fused silica nanostructures from a polyhedral oligomeric silsesquioxane (POSS) resin. Contrary to particle-loaded sacrificial binders, our POSS resin itself constitutes a continuous silicon-oxygen molecular network that forms transparent fused silica at only 650°C. This temperature is 500°C lower than the sintering temperatures for fusing discrete silica particles to a continuum, which brings silica 3D printing below the melting points of essential microsystem materials. Simultaneously, we achieve a fourfold resolution enhancement, which enables visible light nanophotonics. By demonstrating excellent optical quality, mechanical resilience, ease of processing, and coverable size scale, our material sets a benchmark for micro- and nano-3D printing of inorganic solids.
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Affiliation(s)
- J Bauer
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
- Materials Science and Engineering Department, University of California, Irvine, CA 94550, USA
| | - C Crook
- Materials Science and Engineering Department, University of California, Irvine, CA 94550, USA
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3
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Gvindzhiliia G, Sivun D, Naderer C, Jacak J, Klar TA. Low-Fluorescence Starter for Optical 3D Lithography of Sub-40 nm Structures. ACS APPLIED OPTICAL MATERIALS 2023; 1:945-951. [PMID: 37255503 PMCID: PMC10226181 DOI: 10.1021/acsaom.3c00031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/26/2023] [Indexed: 06/01/2023]
Abstract
Stimulated emission depletion (STED) has been used to break the diffraction limit in fluorescence microscopy. Inspired by this success, similar methods were used to reduce the structure size in three-dimensional, subdiffractional optical lithography. So far, only a very limited number of radical polymerization starters proved to be suitable for STED-inspired lithography. In this contribution, we introduce the starter Michler's ethyl ketone (MEK), which has not been used so far for STED-inspired lithography. In contrast to the commonly used 7-diethylamino-3-thenoylcoumarin (DETC), nanostructures written with MEK show low autofluorescence in the visible range. Therefore, MEK is promising for being used as a starter for protein or cell scaffolds in physiological research because the autofluorescence of DETC so far excluded the use of the green emission channel in multicolor fluorescence or confocal microscopy. In turn, because of the weak transitions of MEK in the visible spectrum, STED, in its original sense, cannot be applied to deplete MEK in the outer rim of the point spread function. However, a 660 nm laser can be used for depletion because this wavelength is well within the absorption spectrum of transient states, possibly of triplet states. We show that polymerization can be fully stopped by applying transient state absorption at 660 nm and that structure sizes down to approx. 40 nm in the lateral and axial directions can be achieved, which means 1/20 of the optical wavelength used for writing.
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Affiliation(s)
- Georgii Gvindzhiliia
- Institute
of Applied Physics, Johannes Kepler University
Linz, 4040 Linz, Austria
| | - Dmitry Sivun
- Department
of Medical Engineering, University of Applied
Sciences Upper Austria, 4020 Linz, Austria
| | - Christoph Naderer
- Department
of Medical Engineering, University of Applied
Sciences Upper Austria, 4020 Linz, Austria
| | - Jaroslaw Jacak
- Department
of Medical Engineering, University of Applied
Sciences Upper Austria, 4020 Linz, Austria
| | - Thomas A. Klar
- Institute
of Applied Physics, Johannes Kepler University
Linz, 4040 Linz, Austria
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4
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Bauer J, Meza LR, Schaedler TA, Schwaiger R, Zheng X, Valdevit L. Nanolattices: An Emerging Class of Mechanical Metamaterials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29. [PMID: 28873250 DOI: 10.1002/adma.201701850] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/23/2017] [Indexed: 05/12/2023]
Abstract
In 1903, Alexander Graham Bell developed a design principle to generate lightweight, mechanically robust lattice structures based on triangular cells; this has since found broad application in lightweight design. Over one hundred years later, the same principle is being used in the fabrication of nanolattice materials, namely lattice structures composed of nanoscale constituents. Taking advantage of the size-dependent properties typical of nanoparticles, nanowires, and thin films, nanolattices redefine the limits of the accessible material-property space throughout different disciplines. Herein, the exceptional mechanical performance of nanolattices, including their ultrahigh strength, damage tolerance, and stiffness, are reviewed, and their potential for multifunctional applications beyond mechanics is examined. The efficient integration of architecture and size-affected properties is key to further develop nanolattices. The introduction of a hierarchical architecture is an effective tool in enhancing mechanical properties, and the eventual goal of nanolattice design may be to replicate the intricate hierarchies and functionalities observed in biological materials. Additive manufacturing and self-assembly techniques enable lattice design at the nanoscale; the scaling-up of nanolattice fabrication is currently the major challenge to their widespread use in technological applications.
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Affiliation(s)
- Jens Bauer
- Department of Mechanical and Aerospace Engineering, University of California Irvine, CA, 92697, USA
- Institute for Applied Materials, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, 76344, Germany
| | - Lucas R Meza
- Engineering Department, Trumpington Street, Cambridge, CB2 1PZ, UK
| | | | - Ruth Schwaiger
- Institute for Applied Materials, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, 76344, Germany
| | - Xiaoyu Zheng
- Department of Mechanical Engineering, Virginia Tech, 635 Prices Fork Road, Blacksburg, VA, 24061, USA
| | - Lorenzo Valdevit
- Department of Mechanical and Aerospace Engineering, University of California Irvine, CA, 92697, USA
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5
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Silva DG, Teixeira PA, Gabrielli LH, Junqueira MAFC, Spadoti DH. Full three-dimensional isotropic carpet cloak designed by quasi-conformal transformation optics. OPTICS EXPRESS 2017; 25:23517-23522. [PMID: 29041651 DOI: 10.1364/oe.25.023517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 09/06/2017] [Indexed: 06/07/2023]
Abstract
A fully three-dimensional carpet cloak presenting invisibility in all viewing angles is theoretically demonstrated. The design is developed using transformation optics and three-dimensional quasi-conformal mapping. Parametrization strategy and numerical optimization of the coordinate transformation deploying a quasi-Newton method is applied. A discussion about the minimum achievable anisotropy in the 3D transformation optics is presented. The method allows to reduce the anisotropy in the cloak and an isotropic medium could be considered. Numerical simulations confirm the strategy employed enabling the design of an isotropic reflectionless broadband carpet cloak independently of the incident light direction and polarization.
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6
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Abstract
We report the design, fabrication and experimental verification of an illusion device working at microwave frequencies. A two dimensional topology optimization procedure is employed to find the binary layout of a dielectric coating that, when wrapped around a metallic cylinder, mimics the scattering from a predefined, arbitrarily-shaped dielectric object. Fabrication is carried out with 3D-printing and spatially resolved near field measurements in a waveguide configuration were performed, allowing us to map the illusion effect. Our work provides general guidelines for engineering electromagnetic illusions but can be extended to shape the near and far-field radiations using low index isotropic materials.
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7
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Jiang L, Xiong W, Zhou Y, Liu Y, Huang X, Li D, Baldacchini T, Jiang L, Lu Y. Performance comparison of acrylic and thiol-acrylic resins in two-photon polymerization. OPTICS EXPRESS 2016; 24:13687-701. [PMID: 27410383 DOI: 10.1364/oe.24.013687] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Microfabrication by two-photon polymerization is investigated using resins based on thiol-ene chemistry. In particular, resins containing different amounts of a tetrafunctional acrylic monomer and a tetrafunctional thiol molecule are used to create complex microstructures. We observe the enhancement of several characteristics of two-photon polymerization when using thiol-acrylic resins. Specifically, microfabrication is carried out using higher writing velocities and it produces stronger polymeric microstructures. Furthermore, the amount of shrinkage typically observed in the production of three-dimensional microstructures is reduced also. By means of microspectrometry, we confirm that the thiol-acrylate mixture in TPP resins promote monomer conversion inducing a higher degree of cross-linked network formation.
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8
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Barth DS, Gladden C, Salandrino A, O'Brien K, Ye Z, Mrejen M, Wang Y, Zhang X. Macroscale Transformation Optics Enabled by Photoelectrochemical Etching. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:6131-6136. [PMID: 26332896 DOI: 10.1002/adma.201502322] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 07/29/2015] [Indexed: 06/05/2023]
Abstract
Photoelectrochemical etching of silicon can be used to form lateral refractive index gradients for transformation optical devices. This technique allows the fabrication of macroscale devices with large refractive index gradients. Patterned porous layers can also be lifted from the substrate and transferred to other materials, creating more possibilities for novel devices.
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Affiliation(s)
- David S Barth
- NSF Nano-scale Science and Engineering Center (NSEC), University of California Berkeley, Berkeley, CA, 94720, USA
| | - Christopher Gladden
- NSF Nano-scale Science and Engineering Center (NSEC), University of California Berkeley, Berkeley, CA, 94720, USA
| | - Alessandro Salandrino
- NSF Nano-scale Science and Engineering Center (NSEC), University of California Berkeley, Berkeley, CA, 94720, USA
| | - Kevin O'Brien
- NSF Nano-scale Science and Engineering Center (NSEC), University of California Berkeley, Berkeley, CA, 94720, USA
| | - Ziliang Ye
- NSF Nano-scale Science and Engineering Center (NSEC), University of California Berkeley, Berkeley, CA, 94720, USA
| | - Michael Mrejen
- NSF Nano-scale Science and Engineering Center (NSEC), University of California Berkeley, Berkeley, CA, 94720, USA
| | - Yuan Wang
- NSF Nano-scale Science and Engineering Center (NSEC), University of California Berkeley, Berkeley, CA, 94720, USA
| | - Xiang Zhang
- NSF Nano-scale Science and Engineering Center (NSEC), University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
- Department of Physics, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
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9
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Cheng Q, Wu K, Shi Y, Wang H, Wang GP. Directionally hiding objects and creating illusions above a carpet-like device by reflection holography. Sci Rep 2015; 5:8581. [PMID: 25716451 PMCID: PMC4341210 DOI: 10.1038/srep08581] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/27/2015] [Indexed: 12/04/2022] Open
Abstract
Realization of a perfect invisibility cloak still challenges the current fabricating technologies. Most experiments, if not all, are hence focused on carpet cloaks because of their relatively low requirements to material properties. Nevertheless, present invisibility carpets are used to hide beneath objects. Here, we report a carpet-like device to directionally conceal objects and further to create illusions above it. The device is fabricated through recording a reflection hologram of objects and is used to produce a time-reversed signal to compensate for the information of the objects and further to create light field of another object so as to realize both functions of hiding the objects and creating illusions, respectively. The carpet-like device can work for macroscopic objects at visible wavelength as the distance between objects and device is at decimeter scale. Our carpet-like device to realizing invisibility and creating illusions may provide a robust way for crucial applications of magic camouflaging and anti-detection etc.
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Affiliation(s)
- Qiluan Cheng
- School of Physics and Technology, Wuhan University, Wuhan 430072, Hubei, P. R. China
| | - Kedi Wu
- College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, Guangdong, P. R. China
| | - Yile Shi
- Institute of Information Optics, Zhejiang Normal University, Jinhua 321000, Zhejiang, P. R. China
| | - Hui Wang
- Institute of Information Optics, Zhejiang Normal University, Jinhua 321000, Zhejiang, P. R. China
| | - Guo Ping Wang
- 1] School of Physics and Technology, Wuhan University, Wuhan 430072, Hubei, P. R. China [2] College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, Guangdong, P. R. China
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10
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Moreno I, Jauregui-Sánchez Y, Avendaño-Alejo M. Invisibility assessment: a visual perception approach. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:2244-2248. [PMID: 25401251 DOI: 10.1364/josaa.31.002244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Determining the invisibility of an optical cloak intended to hide something has become a complex problem in recent years. There are many invisibility mechanisms, the performance is quite different from technique to technique, and it is desirable to have a precise metric for their comparison. Here, we propose a simple metric that assesses the perceived invisibility. This invisibility index is based on the fact that the human visual system (HVS) is highly sensitive to spatial frequencies, and then uses the Fourier transform and the contrast sensitivity function of the HVS to assess invisibility.
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11
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Liu S, Xu HX, Zhang HC, Cui TJ. Tunable ultrathin mantle cloak via varactor-diode-loaded metasurface. OPTICS EXPRESS 2014; 22:13403-17. [PMID: 24921534 DOI: 10.1364/oe.22.013403] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We propose a tunable strategy for the ultrathin mantle cloak via metasurface. The tunable cloak is implemented by loading varactor diodes between two neighboring horizontal metallic strips which constitute the metasurface. We demonstrate that the varactor diodes enable the capacitive reactance of the metasurface to be tunable from -157 Ω to -3 Ω when the DC bias voltage is properly changed. The active metasurface is then explored to cloak conformally a conducting cylinder. Both numerical and experiment results show that the cloaking frequency can be continuously controlled from 2.3 GHz to 3.7 GHz by appropriately adjusting the bias voltage. The flexible tunability and good cloaking performance are further examined by the measured field distributions. The advanced features of tunability, low profile, and conformal ability of the ultrathin cloak pave the way for practical applications of cloaking devices.
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12
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Cheng Q, Wu K, Shi Y, Wang H, Wang GP. Directionally hiding objects and creating illusions at visible wavelengths by holography. Sci Rep 2013; 3:1974. [PMID: 23756877 PMCID: PMC3679505 DOI: 10.1038/srep01974] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 05/28/2013] [Indexed: 11/18/2022] Open
Abstract
Invisibility devices have attracted considerable attentions in the last decade. In addition to invisibility cloaks, unidirectional invisibility systems such as carpet-like cloaks and parity-time symmetric structures are also inspiring some specific researching interests due to their relatively simplifying design. However, unidirectional invisibility systems worked generally in just one certain illumination direction. Here, based on time-reversal principle, we present the design and fabrication of a kind of all-dielectric device that could directionally cancel objects and create illusions as the illuminating light was from different directions. Our devices were experimentally realized through holographic technology and could work for macroscopic objects with any reasonable size at visible wavelengths, and hence may take directional invisibility technology a big step towards interesting applications ranging from magic camouflaging, directional detection to super-resolution biomedical imaging.
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Affiliation(s)
- Qiluan Cheng
- School of Physics and Technology, Wuhan University, Wuhan 430072, Hubei, P R China
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13
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Wollhofen R, Katzmann J, Hrelescu C, Jacak J, Klar TA. 120 nm resolution and 55 nm structure size in STED-lithography. OPTICS EXPRESS 2013; 21:10831-40. [PMID: 23669940 DOI: 10.1364/oe.21.010831] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Two-photon direct laser writing (DLW) lithography is limited in the achievable structure size as well as in structure resolution. Adding stimulated emission depletion (STED) to DLW allowed overcoming both restrictions. We now push both to new limits. Using visible light for two-photon DLW (780 nm) and STED (532 nm), we obtain lateral structure sizes of 55 nm, a Sparrow limit of around 100 nm and we present two clearly separated lines spaced only 120 nm apart. The photo-resist used in these experiments is a mixture of tri- and tetra-acrylates and 7-Diethylamino-3-thenoylcoumarin as a photo-starter which can be readily quenched via STED.
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Affiliation(s)
- Richard Wollhofen
- Institute of Applied Physics, Johannes Kepler University Linz, 4040 Linz, Austria
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14
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Abstract
Within the past a few years, transformation optics has emerged as a new research area, since it provides a general methodology and design tool for manipulating electromagnetic waves in a prescribed manner. Using transformation optics, researchers have demonstrated a host of striking phenomena and devices; many of which were only thought possible in science fiction. In this paper, we review the most recent advances in transformation optics. We focus on the theory, design, fabrication and characterization of transformation devices such as the carpet cloak, "Janus" lens and plasmonic cloak at optical frequencies, which allow routing light at the nanoscale. We also provide an outlook of the challenges and future directions in this fascinating area of transformation optics.
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Affiliation(s)
- Yongmin Liu
- NSF Nanoscale Science and Engineering Center-NSEC, 3112 Etcheverry Hall, University of California, Berkeley, CA 94720, USA
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15
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Farhat M, Mühlig S, Rockstuhl C, Lederer F. Scattering cancellation of the magnetic dipole field from macroscopic spheres. OPTICS EXPRESS 2012; 20:13896-13906. [PMID: 22714455 DOI: 10.1364/oe.20.013896] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Based on the scattering cancellation technique we suggest a cloak that allows to conceal macroscopic objects, i.e. objects with an optical size comparable to wavelengths in the visible and whose scattering response is dominated by a magnetic dipole contribution. The key idea in our approach is to use a shell of polaritonic spheres around the object to be cloaked. These spheres exhibit an artificial magnetism. In a systematic investigation, where we progressively increase the complexity of the considered structure, we devise the requirements imposed on the shell and outline how it can be implemented with natural available materials.
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Affiliation(s)
- M Farhat
- Institute of Condensed Matter Theory and Solid State Optics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, D-07743 Jena, Germany.
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16
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Fischer J, Wegener M. Ultrafast polymerization inhibition by stimulated emission depletion for three-dimensional nanolithography. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:OP65-9. [PMID: 22323275 DOI: 10.1002/adma.201103758] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 12/14/2011] [Indexed: 05/05/2023]
Abstract
To identify the depletion mechanism in the stimulated-emission-depletion (STED) inspired photoresist composed of a ketocoumarin photoinitiator in pentaerythritol tetraacrylate, we perform lithography with pulsed excitation and tunable delayed depletion. A fast component can unambiguously be assigned to stimulated emission. Our results allow the systematical optimization of the conditions in next-generation STED direct-laser-writing optical lithography.
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Affiliation(s)
- Joachim Fischer
- Karlsruhe Institute of Technology, Wolfgang-Gaede-Straße 1, Karlsruhe, Germany.
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17
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Abstract
As invisibility cloaking has recently become experimental reality, it is interesting to explore ways to reveal remaining imperfections. In essence, the idea of most invisibility cloaks is to recover the optical path lengths without an object (to be made invisible) by a suitable arrangement around that object. Optical path length is proportional to the time of flight of a light ray or to the optical phase accumulated by a light wave. Thus, time-of-flight images provide a direct and intuitive tool for probing imperfections. Indeed, recent phase-sensitive experiments on the carpet cloak have already made early steps in this direction. In the macroscopic world, time-of-flight images could be measured directly by light detection and ranging (LIDAR). Here, we show calculated time-of-flight images of the conformal Gaussian carpet cloak, the conformal grating cloak, the cylindrical free-space cloak, and of the invisible sphere. All results are obtained by using a ray-velocity equation of motion derived from Fermat's principle.
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Affiliation(s)
- Jad C Halimeh
- Physics Department, Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München, D-80333 München, Germany.
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18
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Cheng Q, Wu K, Wang GP. All dielectric macroscopic cloaks for hiding objects and creating illusions at visible frequencies. OPTICS EXPRESS 2011; 19:23240-23248. [PMID: 22109202 DOI: 10.1364/oe.19.023240] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We introduce and numerically demonstrate a kind of isotropic dielectric macroscopic cloaks for hiding objects and creating illusions at visible frequencies. The cloaks are designed by angular spectrum theory and their working principle is based upon time reversal and conjugation operation. We will demonstrate that the cloaks are capable of hiding both phase-only and lossy objects. The size of the object to be hidden and the distance between the object and the cloak can be in range of millimeter and meter scale, respectively. The results are demonstrated by computer generated holography. Our work may provide a new way for pushing invisibility cloaks a big step toward more realistic fields.
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Affiliation(s)
- Qiluan Cheng
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China
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19
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Ergin T, Fischer J, Wegener M. Optical phase cloaking of 700 nm light waves in the far field by a three-dimensional carpet cloak. PHYSICAL REVIEW LETTERS 2011; 107:173901. [PMID: 22107517 DOI: 10.1103/physrevlett.107.173901] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Indexed: 05/31/2023]
Abstract
Transformation optics is a design tool that connects the geometry of space and propagation of light. Invisibility cloaking is a corresponding benchmark example. Recent experiments at optical frequencies have demonstrated cloaking for the light amplitude only. In this Letter, we demonstrate far-field cloaking of the light phase by interferometric microscope-imaging experiments on the previously introduced three-dimensional carpet cloak at 700 nm wavelength and for arbitrary polarization of light.
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Affiliation(s)
- Tolga Ergin
- Institute of Applied Physics, Karlsruhe Institute of Technology, 76128 Karlsruhe, Germany
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20
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Hiding a realistic object using a broadband terahertz invisibility cloak. Sci Rep 2011; 1:78. [PMID: 22355597 PMCID: PMC3216565 DOI: 10.1038/srep00078] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 08/11/2011] [Indexed: 11/08/2022] Open
Abstract
The invisibility cloak has been a long-standing dream for many researchers over the decades. Using transformation optics, a three-dimensional (3D) object is perceived as having a reduced number of dimensions, making it "undetectable" judging from the scattered field12345. Despite successful experimental demonstration at microwave and optical frequencies6789101112, the spectroscopically important Terahertz (THz) domain13141516 remains unexplored due to difficulties in fabricating cloaking devices that are optically large in all three dimensions. Here, we report the first experimental demonstration of a 3D THz cloaking device fabricated using a scalable Projection Microstereolithography process. The cloak operates at a broad frequency range between 0.3 and 0.6 THz, and is placed over an α-lactose monohydrate absorber with rectangular shape. Characterized using angular-resolved reflection THz time-domain spectroscopy (THz-TDS), the results indicate that the THz invisibility cloak has successfully concealed both the geometrical and spectroscopic signatures of the absorber, making it undetectable to the observer.
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21
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Liang Z, Li J. Scaling two-dimensional photonic crystals for transformation optics. OPTICS EXPRESS 2011; 19:16821-16829. [PMID: 21935043 DOI: 10.1364/oe.19.016821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We propose a method to manipulate Bloch waves in curved photonic crystals for achieving transformation optical devices in two dimensions. Instead of starting from an effectively homogeneous medium, we transform a regular photonic crystal into a curved one in the physical space. A scaling law is established to construct the curved photonic crystal with similar unit cells and different scales, which is made of dielectrics only. A wave compressor and a bending waveguide are designed using dielectrics with indices only from 1 to 4. The approach will be useful in constructing low-loss transformation media requiring small indices, or large anisotropy which is particularly difficult for E-polarization using the conventional effective medium approach.
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Affiliation(s)
- Zixian Liang
- Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong, China
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22
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Wolf TJA, Fischer J, Wegener M, Unterreiner AN. Pump-probe spectroscopy on photoinitiators for stimulated-emission-depletion optical lithography. OPTICS LETTERS 2011; 36:3188-90. [PMID: 21847203 DOI: 10.1364/ol.36.003188] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We report on femtosecond pump-probe experiments on two different photoinitiators in solution. These two molecules have recently appeared as attractive candidates for far-field optical lithography based on stimulated-emission-depletion (STED) inspired approaches aiming at beating Abbe's diffraction limit. For the case of 7-diethylamino-3-thenoylcoumarin (DETC), we find that stimulated emission clearly dominates over excited-state absorption, whereas the opposite holds true for the case of isopropylthioxanthone. We argue that it is desirable that stimulated emission dominates over excited-state absorption as depletion mechanism in STED photoresists. Thus, DETC is an attractive corresponding photoinitiator.
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Affiliation(s)
- Thomas J A Wolf
- Institut fïr Physikalische Chemie, Karlsruhe Institute of Technology (KIT), D-76128 Karlsruhe, Germany.
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