@article{51106, author = {{Schneider, Tobias and Gao, Wenlong and Zentgraf, Thomas and Schumacher, Stefan and Ma, Xuekai}}, journal = {{Nanophotonics}}, title = {{{Topological edge and corner states in coupled wave lattices in nonlinear polariton condensates}}}, doi = {{10.1515/nanoph-2023-0556}}, year = {{2024}}, } @article{51519, author = {{Cui, Tie Jun and Zhang, Shuang and Alu, Andrea and Wegener, Martin and Pendry, John and Luo, Jie and Lai, Yun and Wang, Zuojia and Lin, Xiao and Chen, Hongsheng and Chen, Ping and Wu, Rui-Xin and Yin, Yuhang and Zhao, Pengfei and Chen, Huanyang and Li, Yue and Zhou, Ziheng and Engheta, Nader and Asadchy, V. S. and Simovski, Constantin and Tretyakov, Sergei A and Yang, Biao and Campbell, Sawyer D. and Hao, Yang and Werner, Douglas H and Sun, Shulin and Zhou, Lei and Xu, Su and Sun, Hong-Bo and Zhou, Zhou and Li, Zile and Zheng, Guoxing and Chen, Xianzhong and Li, Tao and Zhu, Shi-Ning and Zhou, Junxiao and Zhao, Junxiang and Liu, Zhaowei and Zhang, Yuchao and Zhang, Qiming and Gu, Min and Xiao, Shumin and Liu, Yongmin and Zhang, Xiaoyu and Tang, Yutao and Li, Guixin and Zentgraf, Thomas and Koshelev, Kirill and Kivshar, Yuri S. and Li, Xin and Badloe, Trevon and Huang, Lingling and Rho, Junsuk and Wang, Shuming and Tsai, Din Ping and Bykov, A. Yu. and Krasavin, Alexey V and Zayats, Anatoly V and McDonnell, Cormac and Ellenbogen, Tal and Luo, Xiangang and Pu, Mingbo and Garcia-Vidal, Francisco J and Liu, Liangliang and Li, Zhuo and Tang, Wenxuan and Ma, Hui Feng and Zhang, Jingjing and Luo, Yu and Zhang, Xuanru and Zhang, Hao Chi and He, Pei Hang and Zhang, Le Peng and Wan, Xiang and Wu, Haotian and Liu, Shuo and Jiang, Wei Xiang and Zhang, Xin Ge and Qiu, Chengwei and Ma, Qian and Liu, Che and Li, Long and Han, Jiaqi and Li, Lianlin and Cotrufo, Michele and Caloz, Christophe and Deck-Léger, Z.-L. and Bahrami, A. and Céspedes, O. and Galiffi, Emanuele and Huidobro, P. A. and Cheng, Qiang and Dai, Jun Yan and Ke, Jun Cheng and Zhang, Lei and Galdi, Vincenzo and Di Renzo, Marco}}, issn = {{2515-7647}}, journal = {{Journal of Physics: Photonics}}, keywords = {{Electrical and Electronic Engineering, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials}}, publisher = {{IOP Publishing}}, title = {{{Roadmap on electromagnetic metamaterials and metasurfaces}}}, doi = {{10.1088/2515-7647/ad1a3b}}, year = {{2024}}, } @article{43421, abstract = {{The achievement of a flat metasurface has realized extraordinary control over light–matter interaction at the nanoscale, enabling widespread use in imaging, holography, and biophotonics. However, three-dimensional metasurfaces with the potential to provide additional light–matter manipulation flexibility attract only little interest. Here, we demonstrate a three-dimensional metasurface scheme capable of providing dual phase control through out-of-plane plasmonic resonance of L-shape antennas. Under circularly polarized excitation at a specific wavelength, the L-shape antennas with rotating orientation angle act as spatially variant three-dimensional tilted dipoles and are able to generate desire phase delay for different polarization components. Generalized Snell's law is achieved for both in-plane and out-of-plane dipole components through arranging such L-shape antennas into arrays. These three-dimensional metasurfaces suggest a route for wavefront modulation and a variety of nanophotonic applications.}}, author = {{Li, Tianyou and Chen, Yanjie and Wang, Yongtian and Zentgraf, Thomas and Huang, Lingling}}, issn = {{0003-6951}}, journal = {{Applied Physics Letters}}, keywords = {{Physics and Astronomy (miscellaneous)}}, number = {{14}}, publisher = {{AIP Publishing}}, title = {{{Three-dimensional dipole momentum analog based on L-shape metasurface}}}, doi = {{10.1063/5.0142389}}, volume = {{122}}, year = {{2023}}, } @inproceedings{43051, abstract = {{We demonstrate the numerical and experimental realization of optimized optical traveling-wave antennas made of low-loss dielectric materials. These antennas exhibit highly directive radiation patterns and our studies reveal that this nature comes from two dominant guided TE modes excited in the waveguide-like director of the antenna, in addition to the leaky modes. The optimized antennas possess a broadband nature and have a nearunity radiation efficiency at an operational wavelength of 780 nm. Compared to the previously studied plasmonic antennas for photon emission, our all-dielectric approach demonstrates a new class of highly directional, low-loss, and broadband optical antennas.}}, author = {{Farheen, Henna and Yan, Lok-Yee and Leuteritz, Till and Qiao, Siqi and Spreyer, Florian and Schlickriede, Christian and Quiring, Viktor and Eigner, Christof and Silberhorn, Christine and Zentgraf, Thomas and Linden, Stefan and Myroshnychenko, Viktor and Förstner, Jens}}, booktitle = {{Integrated Optics: Devices, Materials, and Technologies XXVII}}, editor = {{García-Blanco, Sonia M. and Cheben, Pavel}}, keywords = {{tet_topic_opticalantenna}}, pages = {{124241E}}, publisher = {{SPIE}}, title = {{{Tailoring the directive nature of optical waveguide antennas}}}, doi = {{10.1117/12.2658921}}, year = {{2023}}, } @article{44097, abstract = {{We present strong enhancement of third harmonic generation in an amorphous silicon metasurface consisting of elliptical nano resonators. We show that this enhancement originates from a new type of multi-mode Fano mechanism. These ‘Super-Fano’ resonances are investigated numerically in great detail using full-wave simulations. The theoretically predicted behavior of the metasurface is experimentally verified by linear and nonlinear transmission spectroscopy. Moreover, quantitative nonlinear measurements are performed, in which an absolute conversion efficiency as high as ηmax ≈ 2.8 × 10−7 a peak power intensity of 1.2 GW cm−2 is found. Compared to an unpatterned silicon film of the same thickness amplification factors of up to ~900 are demonstrated. Our results pave the way to exploiting a strong Fano-type multi-mode coupling in metasurfaces for high THG in potential applications.}}, author = {{Hähnel, David and Golla, Christian and Albert, Maximilian and Zentgraf, Thomas and Myroshnychenko, Viktor and Förstner, Jens and Meier, Cedrik}}, issn = {{2047-7538}}, journal = {{Light: Science & Applications}}, keywords = {{tet_topic_meta}}, number = {{1}}, pages = {{97}}, publisher = {{Springer Nature}}, title = {{{A multi-mode super-fano mechanism for enhanced third harmonic generation in silicon metasurfaces}}}, doi = {{https://doi.org/10.1038/s41377-023-01134-1}}, volume = {{12}}, year = {{2023}}, } @article{44044, abstract = {{Dispersion is present in every optical setup and is often an undesired effect, especially in nonlinear-optical experiments where ultrashort laser pulses are needed. Typically, bulky pulse compressors consisting of gratings or prisms are used to address this issue by precompensating the dispersion of the optical components. However, these devices are only able to compensate for a part of the dispersion (second-order dispersion). Here, we present a compact pulse-shaping device that uses plasmonic metasurfaces to apply an arbitrarily designed spectral phase delay allowing for a full dispersion control. Furthermore, with specific phase encodings, this device can be used to temporally reshape the incident laser pulses into more complex pulse forms such as a double pulse. We verify the performance of our device by using an SHG-FROG measurement setup together with a retrieval algorithm to extract the dispersion that our device applies to an incident laser pulse.}}, author = {{Geromel, René and Georgi, Philip and Protte, Maximilian and Lei, Shiwei and Bartley, Tim and Huang, Lingling and Zentgraf, Thomas}}, issn = {{1530-6984}}, journal = {{Nano Letters}}, keywords = {{Mechanical Engineering, Condensed Matter Physics, General Materials Science, General Chemistry, Bioengineering}}, number = {{8}}, pages = {{3196 -- 3201}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Compact Metasurface-Based Optical Pulse-Shaping Device}}}, doi = {{10.1021/acs.nanolett.2c04980}}, volume = {{23}}, year = {{2023}}, } @article{45868, abstract = {{Perfect vector vortex beams (PVVBs) have attracted considerable interest due to their peculiar optical features. PVVBs are typically generated through the superposition of perfect vortex beams, which suffer from the limited number of topological charges (TCs). Furthermore, dynamic control of PVVBs is desirable and has not been reported. We propose and experimentally demonstrate hybrid grafted perfect vector vortex beams (GPVVBs) and their dynamic control. Hybrid GPVVBs are generated through the superposition of grafted perfect vortex beams with a multifunctional metasurface. The generated hybrid GPVVBs possess spatially variant rates of polarization change due to the involvement of more TCs. Each hybrid GPVVB includes different GPVVBs in the same beam, adding more design flexibility. Moreover, these beams are dynamically controlled with a rotating half waveplate. The generated dynamic GPVVBs may find applications in the fields where dynamic control is in high demand, including optical encryption, dense data communication, and multiple particle manipulation.}}, author = {{Ahmed, Hammad and Ansari, Muhammad Afnan and Li, Yan and Zentgraf, Thomas and Mehmood, Muhammad Qasim and Chen, Xianzhong}}, issn = {{2041-1723}}, journal = {{Nature Communications}}, keywords = {{General Physics and Astronomy, General Biochemistry, Genetics and Molecular Biology, General Chemistry, Multidisciplinary}}, number = {{1}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Dynamic control of hybrid grafted perfect vector vortex beams}}}, doi = {{10.1038/s41467-023-39599-8}}, volume = {{14}}, year = {{2023}}, } @inproceedings{46485, abstract = {{We present a miniaturized pulse shaping device that creates an arbitrary dispersion through the interaction of multiple metasurfaces on less than 2 mm3 volume. For this, a metalens and a grating-metasurface between two silver mirrors are fabricated. The grating contains further phase information to achieve the device's pulse shaping functionality.}}, author = {{Geromel, René and Georgi, Philip and Protte, Maximilian and Bartley, Tim and Huang, Lingling and Zentgraf, Thomas}}, booktitle = {{CLEO: Fundamental Science 2023}}, location = {{San Jose, USA}}, publisher = {{Optica Publishing Group}}, title = {{{Dispersion control with integrated plasmonic metasurfaces}}}, doi = {{10.1364/cleo_fs.2023.fth4d.3}}, year = {{2023}}, } @inbook{47543, author = {{Zentgraf, Thomas}}, booktitle = {{Fundamentals and Applications of Nonlinear Nanophotonics}}, editor = {{Panoiu, Nicoae C.}}, isbn = {{978-0-323-90614-2}}, publisher = {{Elsevier}}, title = {{{Symmetry governed nonlinear selection rules in nanophotonics }}}, doi = {{10.1016/B978-0-323-90614-2.00011-0}}, year = {{2023}}, } @article{49607, abstract = {{In this work, we utilize thin dielectric meta-atoms placed on a silver substrate to efficiently enhance and manipulate the third-harmonic generation. We theoretically and experimentally reveal that when the structural symmetry of the meta-atom is incompatible with the lattice symmetry of an array, some generalized nonlinear geometric phases appear, which offers new possibilities for harmonic generation control beyond the accessible symmetries governed by the selection rule. The underlying mechanism is attributed to the modified rotation of the effective principal axis of a dense meta-atom array, where the strong coupling among the units gives rise to a generalized linear geometric phase modulation of the pump light. Therefore, nonlinear geometric phases carried by third-harmonic emissions are the natural result of the wave-mixing process among the modes excited at the fundamental frequency. This mechanism further points out a new strategy to predict the nonlinear geometric phases delivered by the nanostructures according to their linear responses. Our design is simple and efficient and offers alternatives for the nonlinear meta-devices that are capable of flexible photon generation and manipulation.}}, author = {{Liu, Bingyi and Geromel, René and Su, Zhaoxian and Guo, Kai and Wang, Yongtian and Guo, Zhongyi and Huang, Lingling and Zentgraf, Thomas}}, issn = {{2330-4022}}, journal = {{ACS Photonics}}, keywords = {{Electrical and Electronic Engineering, Atomic and Molecular Physics, and Optics, Biotechnology, Electronic, Optical and Magnetic Materials}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Nonlinear Dielectric Geometric-Phase Metasurface with Simultaneous Structure and Lattice Symmetry Design}}}, doi = {{10.1021/acsphotonics.3c01163}}, year = {{2023}}, } @article{40513, abstract = {{Geometric-phase dielectric meta-lenses made of silicon with high numerical aperture and short focal lengths are fabricated and characterised. For circularly polarised light, the same meta-lens can act as a converging or diverging lens, depending on the handedness of the circular polarisation. This effect enables application for optical tweezers that trap or release µm-size polymer beads floating in a microfluidic channel on demand. An electrically addressable polarisation converter based on liquid crystals may be used to switch between the two states of polarisation, at which the light transmitted through the meta-lens is focused (trapping) or defocussed (releasing), respectively.}}, author = {{Geromel, René and Rennerich, Roman and Zentgraf, Thomas and Kitzerow, Heinz-Siegfried}}, journal = {{Liquid Crystals}}, number = {{7-10}}, pages = {{1193--1203}}, publisher = {{Taylor & Francis}}, title = {{{Geometric-phase metalens to be used for tunable optical tweezers in microfluidics}}}, doi = {{10.1080/02678292.2023.2171146}}, volume = {{50}}, year = {{2023}}, } @article{26747, abstract = {{Metasurfaces provide applications for a variety of flat elements and devices due to the ability to modulate light with subwavelength structures. The working principle meanwhile gives rise to the crucial problem and challenge to protect the metasurface from dust or clean the unavoidable contaminants during daily usage. Here, taking advantage of the intelligent bioinspired surfaces which exhibit self-cleaning properties, a versatile dielectric metasurface benefiting from the obtained superhydrophilic or quasi-superhydrophobic states is shown. The design is realized by embedding the metasurface inside a large area of wettability supporting structures, which is highly efficient in fabrication, and achieves both optical and wettability functionality at the same time. The superhydrophilic state enables an enhanced optical response with water, while the quasi-superhydrophobic state imparts the fragile antennas an ability to self-clean dust contamination. Furthermore, the metasurface can be easily switched and repeated between these two wettability or functional states by appropriate treatments in a repeatable way, without degrading the optical performance. The proposed design strategy will bring new opportunities to smart metasurfaces with improved optical performance, versatility, and physical stability.}}, author = {{Lu, Jinlong and Sain, Basudeb and Georgi, Philip and Protte, Maximilian and Bartley, Tim and Zentgraf, Thomas}}, issn = {{2195-1071}}, journal = {{Advanced Optical Materials}}, number = {{1}}, publisher = {{Wiley}}, title = {{{A Versatile Metasurface Enabling Superwettability for Self‐Cleaning and Dynamic Color Response}}}, doi = {{10.1002/adom.202101781}}, volume = {{10}}, year = {{2022}}, } @article{30195, abstract = {{While plasmonic particles can provide optical resonances in a wide spectral range from the lower visible up to the near-infrared, often, symmetry effects are utilized to obtain particular optical responses. By breaking certain spatial symmetries, chiral structures arise and provide robust chiroptical responses to these plasmonic resonances. Here, we observe strong chiroptical responses in the linear and nonlinear optical regime for chiral L-handed helicoid-III nanoparticles and quantify them by means of an asymmetric factor, the so-called g-factor. We calculate the linear optical g-factors for two distinct chiroptical resonances to −0.12 and –0.43 and the nonlinear optical g-factors to −1.45 and −1.63. The results demonstrate that the chirality of the helicoid-III nanoparticles is strongly enhanced in the nonlinear regime.}}, author = {{Spreyer, Florian and Mun, Jungho and Kim, Hyeohn and Kim, Ryeong Myeong and Nam, Ki Tae and Rho, Junsuk and Zentgraf, Thomas}}, issn = {{2330-4022}}, journal = {{ACS Photonics}}, keywords = {{Electrical and Electronic Engineering, Atomic and Molecular Physics, and Optics, Biotechnology, Electronic, Optical and Magnetic Materials}}, number = {{3}}, pages = {{784–792}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Second Harmonic Optical Circular Dichroism of Plasmonic Chiral Helicoid-III Nanoparticles}}}, doi = {{10.1021/acsphotonics.1c00882}}, volume = {{9}}, year = {{2022}}, } @article{29902, author = {{Reineke Matsudo, Bernhard and Sain, Basudeb and Carletti, Luca and Zhang, Xue and Gao, Wenlong and Angelis, Costantino and Huang, Lingling and Zentgraf, Thomas}}, issn = {{2198-3844}}, journal = {{Advanced Science}}, keywords = {{General Physics and Astronomy, General Engineering, Biochemistry, Genetics and Molecular Biology (miscellaneous), General Materials Science, General Chemical Engineering, Medicine (miscellaneous)}}, number = {{12}}, publisher = {{Wiley}}, title = {{{Efficient Frequency Conversion with Geometric Phase Control in Optical Metasurfaces}}}, doi = {{10.1002/advs.202104508}}, volume = {{9}}, year = {{2022}}, } @article{30964, author = {{Gao, Wenlong and Sain, Basudeb and Zentgraf, Thomas}}, issn = {{2331-7019}}, journal = {{Physical Review Applied}}, keywords = {{General Physics and Astronomy}}, number = {{4}}, publisher = {{American Physical Society (APS)}}, title = {{{Spin-Orbit Interaction of Light Enabled by Negative Coupling in High-Quality-Factor Optical Metasurfaces}}}, doi = {{10.1103/physrevapplied.17.044022}}, volume = {{17}}, year = {{2022}}, } @article{32088, abstract = {{Subwavelength dielectric resonators assembled into metasurfaces have become a versatile tool for miniaturizing optical components approaching the nanoscale. An important class of metasurface functionalities is associated with asymmetry in both the generation and transmission of light with respect to reversals of the positions of emitters and receivers. The nonlinear light–matter interaction in metasurfaces offers a promising pathway towards miniaturization of the asymmetric control of light. Here we demonstrate asymmetric parametric generation of light in nonlinear metasurfaces. We assemble dissimilar nonlinear dielectric resonators into translucent metasurfaces that produce images in the visible spectral range on being illuminated by infrared radiation. By design, the metasurfaces produce different and completely independent images for the reversed direction of illumination, that is, when the positions of the infrared emitter and the visible light receiver are exchanged. Nonlinearity-enabled asymmetric control of light by subwavelength resonators paves the way towards novel nanophotonic components via dense integration of large quantities of nonlinear resonators into compact metasurface designs.}}, author = {{Kruk, Sergey S. and Wang, Lei and Sain, Basudeb and Dong, Zhaogang and Yang, Joel and Zentgraf, Thomas and Kivshar, Yuri}}, issn = {{1749-4885}}, journal = {{Nature Photonics}}, keywords = {{Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials}}, pages = {{561–565}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Asymmetric parametric generation of images with nonlinear dielectric metasurfaces}}}, doi = {{10.1038/s41566-022-01018-7}}, volume = {{16}}, year = {{2022}}, } @inproceedings{34465, author = {{laeim, Huddad and Schlickriede, Christian and Chaisakul, Papichaya and Chattham, Nattaporn and Panitchakan, Hathai and Siangchaew, Krisda and Zentgraf, Thomas and Pattanaporhratana, Apichart}}, booktitle = {{Metamaterials, Metadevices, and Metasystems 2022}}, editor = {{Engheta, Nader and Noginov, Mikhail A. and Zheludev, Nikolay I.}}, publisher = {{SPIE}}, title = {{{Design and investigation of a metalens for efficiency enhancement of laser-waveguide coupling in a limited space system}}}, doi = {{10.1117/12.2629789}}, year = {{2022}}, } @article{31329, abstract = {{Highly directive antennas with the ability of shaping radiation patterns in desired directions are essential for efficient on-chip optical communication with reduced cross talk. In this paper, we design and optimize three distinct broadband traveling-wave tantalum pentoxide antennas exhibiting highly directional characteristics. Our antennas contain a director and reflector deposited on a glass substrate, which are excited by a dipole emitter placed in the feed gap between the two elements. Full-wave simulations in conjunction with global optimization provide structures with an enhanced linear directivity as high as 119 radiating in the substrate. The high directivity is a result of the interplay between two dominant TE modes and the leaky modes present in the antenna director. Furthermore, these low-loss dielectric antennas exhibit a near-unity radiation efficiency at the operational wavelength of 780 nm and maintain a broad bandwidth. Our numerical results are in good agreement with experimental measurements from the optimized antennas fabricated using a two-step electron-beam lithography, revealing the highly directive nature of our structures. We envision that our antenna designs can be conveniently adapted to other dielectric materials and prove instrumental for inter-chip optical communications and other on-chip applications.}}, author = {{Farheen, Henna and Yan, Lok-Yee and Quiring, Viktor and Eigner, Christof and Zentgraf, Thomas and Linden, Stefan and Förstner, Jens and Myroshnychenko, Viktor}}, issn = {{1094-4087}}, journal = {{Optics Express}}, keywords = {{tet_topic_opticalantenna}}, number = {{11}}, pages = {{19288}}, publisher = {{Optica Publishing Group}}, title = {{{Broadband optical Ta2O5 antennas for directional emission of light}}}, doi = {{10.1364/oe.455815}}, volume = {{30}}, year = {{2022}}, } @article{31480, abstract = {{Optical geometric phase encoded by in-plane spatial orientation of microstructures has promoted the rapid development of numerous functional meta-devices. However, pushing the concept of the geometric phase toward the acoustic community still faces challenges. In this work, we utilize two acoustic nonlocal metagratings that could support a direct conversion between an acoustic plane wave and a designated vortex mode to obtain the acoustic geometric phase, in which an orbital angular momentum conversion process plays a vital role. In addition, we realize the acoustic geometric phases of different orders by merely varying the orientation angle of the acoustic nonlocal metagratings. Intriguingly, according to our developed theory, we reveal that the reflective acoustic geometric phase, which is twice the transmissive one, can be readily realized by transferring the transmitted configuration to a reflected one. Both the theoretical study and experimental measurements verify the announced transmissive and reflective acoustic geometric phases. Moreover, the reconfigurability and continuous phase modulation that covers the 2π range shown by the acoustic geometric phases provide us with the alternatives in advanced acoustic wavefront control.}}, author = {{Liu, Bingyi and Zhou, Zhiling and Wang, Yongtian and Zentgraf, Thomas and Li, Yong and Huang, Lingling}}, issn = {{0003-6951}}, journal = {{Applied Physics Letters}}, keywords = {{Physics and Astronomy (miscellaneous)}}, number = {{21}}, publisher = {{AIP Publishing}}, title = {{{Experimental verification of the acoustic geometric phase}}}, doi = {{10.1063/5.0091474}}, volume = {{120}}, year = {{2022}}, } @article{28254, abstract = {{With the rapid advances of functional dielectric metasurfaces and their integration on on-chip nanophotonic devices, the necessity of metasurfaces working in different environments, especially in biological applications, arose. However, the metasurfaces’ performance is tied to the unit cell’s efficiency and ultimately the surrounding environment it was designed for, thus reducing its applicability if exposed to altering refractive index media. Here, we report a method to increase a metasurface’s versatility by covering the high-index metasurface with a low index porous SiO2 film, protecting the metasurface from environmental changes while keeping the working efficiency unchanged. We show, that a covered metasurface retains its functionality even when exposed to fluidic environments.}}, author = {{Geromel, René and Weinberger, Christian and Brormann, Katja and Tiemann, Michael and Zentgraf, Thomas}}, issn = {{2159-3930}}, journal = {{Optical Materials Express}}, number = {{1}}, pages = {{13--21}}, publisher = {{Optica}}, title = {{{Porous SiO2 coated dielectric metasurface with consistent performance independent of environmental conditions}}}, doi = {{10.1364/ome.444264}}, volume = {{12}}, year = {{2022}}, }