@article{17390,
  author       = {{Chantakit, Teanchai and Schlickriede, Christian and Sain, Basudeb and Meyer, Fabian and Weiss, Thomas and Chattham, Nattaporn and Zentgraf, Thomas}},
  issn         = {{2327-9125}},
  journal      = {{Photonics Research}},
  number       = {{9}},
  pages        = {{1435--1440}},
  publisher    = {{OSA}},
  title        = {{{All-dielectric silicon metalens for two-dimensional particle manipulation in optical tweezers}}},
  doi          = {{10.1364/prj.389200}},
  volume       = {{8}},
  year         = {{2020}},
}

@article{17523,
  abstract     = {{<jats:p>Compact and robust cold atom sources are increasingly important for quantum research, especially for transferring cutting-edge quantum science into practical applications. In this study, we report on a novel scheme that uses a metasurface optical chip to replace the conventional bulky optical elements used to produce a cold atomic ensemble with a single incident laser beam, which is split by the metasurface into multiple beams of the desired polarization states. Atom numbers ~10<jats:sup>7</jats:sup> and temperatures (about 35 μK) of relevance to quantum sensing are achieved in a compact and robust fashion. Our work highlights the substantial progress toward fully integrated cold atom quantum devices by exploiting metasurface optical chips, which may have great potential in quantum sensing, quantum computing, and other areas.</jats:p>}},
  author       = {{Zhu, Lingxiao and Liu, Xuan and Sain, Basudeb and Wang, Mengyao and Schlickriede, Christian and Tang, Yutao and Deng, Junhong and Li, Kingfai and Yang, Jun and Holynski, Michael and Zhang, Shuang and Zentgraf, Thomas and Bongs, Kai and Lien, Yu-Hung and Li, Guixin}},
  issn         = {{2375-2548}},
  journal      = {{Science Advances}},
  number       = {{31}},
  publisher    = {{American Association for the Advancement of Science}},
  title        = {{{A dielectric metasurface optical chip for the generation of cold atoms}}},
  doi          = {{10.1126/sciadv.abb6667}},
  volume       = {{6}},
  year         = {{2020}},
}

@inbook{20847,
  author       = {{Zentgraf, Thomas and Chen, Shumei and Li, Guixin and Zhang, Shuang}},
  booktitle    = {{Nanoantennas and Plasmonics: Modelling, design and fabrication}},
  editor       = {{Werner, Douglas H. and Campbell, Sawyer D. and Kang, Lei}},
  publisher    = {{The Institution of Engineering and Technology}},
  title        = {{{Plasmonic metasurfaces for controlling harmonic generations}}},
  doi          = {{10.1049/SBEW540E_ch8}},
  year         = {{2020}},
}

@article{16839,
  author       = {{Sain, Basudeb and Zentgraf, Thomas}},
  issn         = {{2047-7538}},
  journal      = {{Light: Science & Applications}},
  pages        = {{67}},
  title        = {{{Metasurfaces help lasers to mode-lock}}},
  doi          = {{10.1038/s41377-020-0312-1}},
  volume       = {{9}},
  year         = {{2020}},
}

@article{16931,
  author       = {{Zhou, Hongqiang and Sain, Basudeb and Wang, Yongtian and Schlickriede, Christian and Zhao, Ruizhe and Zhang, Xue and Wei, Qunshuo and Li, Xiaowei and Huang, Lingling and Zentgraf, Thomas}},
  issn         = {{1936-0851}},
  journal      = {{ACS Nano}},
  number       = {{5}},
  pages        = {{5553–5559}},
  title        = {{{Polarization-Encrypted Orbital Angular Momentum Multiplexed Metasurface Holography}}},
  doi          = {{10.1021/acsnano.9b09814}},
  volume       = {{14}},
  year         = {{2020}},
}

@article{16944,
  author       = {{Schlickriede, Christian and Kruk, Sergey S. and Wang, Lei and Sain, Basudeb and Kivshar, Yuri and Zentgraf, Thomas}},
  issn         = {{1530-6984}},
  journal      = {{Nano Letters}},
  number       = {{6}},
  pages        = {{4370–4376}},
  title        = {{{Nonlinear imaging with all-dielectric metasurfaces}}},
  doi          = {{10.1021/acs.nanolett.0c01105}},
  volume       = {{20}},
  year         = {{2020}},
}

@article{15480,
  abstract     = {{<jats:p>The nonlinear processes of frequency conversion such as second harmonic generation (SHG) usually obey certain selection rules, resulting from the preservation of different kinds of physical quantities, e.g. the angular momentum. For the SHG created by a monolayer of transition-metal dichalcogenides (TMDCs) such as WS<jats:sub>2</jats:sub>, the valley-exciton locked selection rule predicts an SHG signal in the cross-polarization state. By combining plasmonic nanostructures with a monolayer of TMDC, a hybrid metasurface is realized, which affects this nonlinear process because of an additional polarization conversion process. Here, we observe that the plasmonic metasurface modifies the light-matter interaction with the TMDC, resulting in an SHG signal that is co-polarized with respect to the incident field, which is usually forbidden for the monolayers of TMDC. We fabricate such hybrid metasurfaces by placing plasmonic nanorods on top of a monolayer WS<jats:sub>2</jats:sub> and study the valley-exciton locked SHG emission from such system for different parameters, such as wavelength and polarization. Furthermore, we show the potential of the hybrid metasurface for tailoring nonlinear processes by adding additional phase information to the SHG signal using the Pancharatnam-Berry phase effect. This allows direct tailoring of the SHG emission to the far-field.</jats:p>}},
  author       = {{Spreyer, Florian and Zhao, Ruizhe and Huang, Lingling and Zentgraf, Thomas}},
  issn         = {{2192-8614}},
  journal      = {{Nanophotonics}},
  number       = {{2}},
  pages        = {{351–360}},
  title        = {{{Second harmonic imaging of plasmonic Pancharatnam-Berry phase metasurfaces coupled to monolayers of WS2}}},
  doi          = {{10.1515/nanoph-2019-0378}},
  volume       = {{9}},
  year         = {{2020}},
}

@article{16197,
  abstract     = {{Nonlinear Pancharatnam–Berry phase metasurfaces facilitate the nontrivial phase modulation for frequency conversion processes by leveraging photon‐spin dependent nonlinear geometric‐phases. However, plasmonic metasurfaces show some severe limitation for nonlinear frequency conversion due to the intrinsic high ohmic loss and low damage threshold of plasmonic nanostructures. Here, the nonlinear geometric‐phases associated with the third‐harmonic generation process occurring in all‐dielectric metasurfaces is studied systematically, which are composed of silicon nanofins with different in‐plane rotational symmetries. It is found that the wave coupling among different field components of the resonant fundamental field gives rise to the appearance of different nonlinear geometric‐phases of the generated third‐harmonic signals. The experimental observations of the nonlinear beam steering and nonlinear holography realized in this work by all‐dielectric geometric‐phase metasurfaces are well explained with the developed theory. This work offers a new physical picture to understand the nonlinear optical process occurring at nanoscale dielectric resonators and will help in the design of nonlinear metasurfaces with tailored phase properties.}},
  author       = {{Liu, Bingyi and Sain, Basudeb and Reineke, Bernhard and Zhao, Ruizhe and Meier, Cedrik and Huang, Lingling and Jiang, Yongyuan and Zentgraf, Thomas}},
  issn         = {{2195-1071}},
  journal      = {{Advanced Optical Materials}},
  number       = {{9}},
  publisher    = {{Wiley}},
  title        = {{{Nonlinear Wavefront Control by Geometric-Phase Dielectric Metasurfaces: Influence of Mode Field and Rotational Symmetry}}},
  doi          = {{10.1002/adom.201902050}},
  volume       = {{8}},
  year         = {{2020}},
}

@article{16301,
  author       = {{Atorf, Bernhard and Mühlenbernd, Holger and Zentgraf, Thomas and Kitzerow, Heinz-Siegfried}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  number       = {{6}},
  pages        = {{8898--8908}},
  title        = {{{All-optical switching of a dye-doped liquid crystal plasmonic metasurface}}},
  doi          = {{10.1364/oe.383877}},
  volume       = {{28}},
  year         = {{2020}},
}

@article{8797,
  abstract     = {{Free from phase-matching constraints, plasmonic metasurfaces have contributed significantly to the control of optical nonlinearity and enhancement of nonlinear generation efficiency by engineering subwavelength meta-atoms. However, high dissipative losses and inevitable thermal heating limit their applicability in nonlinear nanophotonics. All-dielectric metasurfaces, supporting both electric and magnetic Mie-type resonances in their nanostructures, have appeared as a promising alternative to nonlinear plasmonics. High-index dielectric nanostructures, allowing additional magnetic resonances, can induce magnetic nonlinear effects, which, along with electric nonlinearities, increase the nonlinear conversion efficiency. In addition, low dissipative losses and high damage thresholds provide an extra degree of freedom for operating at high pump intensities, resulting in a considerable enhancement of the nonlinear processes. We discuss the current state of the art in the intensely developing area of all-dielectric nonlinear nanostructures and metasurfaces, including the role of Mie modes, Fano resonances, and anapole moments for harmonic generation, wave mixing, and ultrafast optical switching. Furthermore, we review the recent progress in the nonlinear phase and wavefront control using all-dielectric metasurfaces. We discuss techniques to realize all-dielectric metasurfaces for multifunctional applications and generation of second-order nonlinear processes from complementary metal–oxide–semiconductor-compatible materials.}},
  author       = {{Sain, Basudeb and Meier, Cedrik and Zentgraf, Thomas}},
  issn         = {{2577-5421}},
  journal      = {{Advanced Photonics}},
  number       = {{2}},
  pages        = {{024002}},
  title        = {{{Nonlinear optics in all-dielectric nanoantennas and metasurfaces: a review}}},
  doi          = {{10.1117/1.ap.1.2.024002}},
  volume       = {{1}},
  year         = {{2019}},
}

@article{9897,
  author       = {{Protte, Maximilian and Weber, Nils and Golla, Christian and Zentgraf, Thomas and Meier, Cedrik}},
  issn         = {{0021-8979}},
  journal      = {{Journal of Applied Physics}},
  title        = {{{Strong nonlinear optical response from ZnO by coupled and lattice-matched nanoantennas}}},
  doi          = {{10.1063/1.5093257}},
  volume       = {{125}},
  year         = {{2019}},
}

@article{11953,
  abstract     = {{As flexible optical devices that can manipulate the phase and amplitude of light, metasurfaces would clearly benefit from directional optical properties. However, single layer metasurface systems consisting of two-dimensional nanoparticle arrays exhibit only a weak spatial asymmetry perpendicular to the surface and therefore have mostly symmetric transmission features. Here, we present a metasurface design principle for nonreciprocal polarization encryption of holographic images. Our approach is based on a two-layer plasmonic metasurface design that introduces a local asymmetry and generates a bidirectional functionality with full phase and amplitude control of the transmitted light. The encoded hologram is designed to appear in a particular linear cross-polarization channel, while it is disappearing in the reverse propagation direction. Hence, layered metasurface systems can feature asymmetric transmission with full phase and amplitude control and therefore expand the design freedom in nanoscale optical devices toward asymmetric information processing and security features for anticounterfeiting applications.}},
  author       = {{Frese, Daniel and Wei, Qunshuo and Wang, Yongtian and Huang, Lingling and Zentgraf, Thomas}},
  issn         = {{1530-6984}},
  journal      = {{Nano Letters}},
  number       = {{6}},
  pages        = {{3976--3980}},
  title        = {{{Nonreciprocal Asymmetric Polarization Encryption by Layered Plasmonic Metasurfaces}}},
  doi          = {{10.1021/acs.nanolett.9b01298}},
  volume       = {{19}},
  year         = {{2019}},
}

@article{11955,
  author       = {{Li, Tianyou and Wei, Qunshuo and Reineke, Bernhard and Walter, Felicitas and Wang, Yongtian and Zentgraf, Thomas and Huang, Lingling}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  number       = {{15}},
  pages        = {{21153--21162}},
  title        = {{{Reconfigurable metasurface hologram by utilizing addressable dynamic pixels}}},
  doi          = {{10.1364/oe.27.021153}},
  volume       = {{27}},
  year         = {{2019}},
}

@article{12917,
  author       = {{Reineke, Bernhard and Sain, Basudeb and Zhao, Ruizhe and Carletti, Luca and Liu, Bingyi and Huang, Lingling and de Angelis, Costantino and Zentgraf, Thomas}},
  issn         = {{1530-6984}},
  journal      = {{Nano Letters}},
  number       = {{9}},
  pages        = {{6585–6591}},
  title        = {{{Silicon metasurfaces for third harmonic geometric phase manipulation and multiplexed holography}}},
  doi          = {{10.1021/acs.nanolett.9b02844}},
  volume       = {{19}},
  year         = {{2019}},
}

@article{12919,
  author       = {{Georgi, Philip and Massaro, Marcello and Luo, Kai Hong and Sain, Basudeb and Montaut, Nicola and Herrmann, Harald and Weiss, Thomas and Li, Guixin and Silberhorn, Christine and Zentgraf, Thomas}},
  issn         = {{2047-7538}},
  journal      = {{Light: Science & Applications}},
  pages        = {{70}},
  title        = {{{Metasurface interferometry toward quantum sensors}}},
  doi          = {{10.1038/s41377-019-0182-6}},
  volume       = {{8}},
  year         = {{2019}},
}

@article{14870,
  author       = {{Wei, Qunshuo and Sain, Basudeb and Wang, Yongtian and Reineke, Bernhard and Li, Xiaowei and Huang, Lingling and Zentgraf, Thomas}},
  issn         = {{1530-6984}},
  journal      = {{Nano Letters}},
  number       = {{12}},
  pages        = {{8964–8971}},
  title        = {{{Simultaneous Spectral and Spatial Modulation for Color Printing and Holography Using All-dielectric Metasurfaces}}},
  doi          = {{10.1021/acs.nanolett.9b03957}},
  volume       = {{19}},
  year         = {{2019}},
}

@article{10282,
  author       = {{Lin, Zemeng and Huang, Lingling and Zhao, Ruizhe and Wei, Qunshuo and Zentgraf, Thomas and Wang, Yongtian and Li, Xiaowei}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  number       = {{13}},
  pages        = {{18740--18750}},
  title        = {{{Dynamic control of mode modulation and spatial multiplexing using hybrid metasurfaces}}},
  doi          = {{10.1364/oe.27.018740}},
  volume       = {{27}},
  year         = {{2019}},
}

@article{13650,
  abstract     = {{<jats:p>Surfaces covered with layers of ultrathin nanoantenna structures—so called metasurfaces have recently been proven capable of completely controlling phase of light. Metalenses have emerged from the advance in the development of metasurfaces providing a new basis for recasting traditional lenses into thin, planar optical components capable of focusing light. The lens made of arrays of plasmonic gold nanorods were fabricated on a glass substrate by using electron beam lithography. A 1064 nm laser was used to create a high intensity circularly polarized light focal spot through metalens of focal length 800 µm, N.A. = 0.6 fabricated based on Pancharatnam-Berry phase principle. We demonstrated that optical rotation of birefringent nematic liquid crystal droplets trapped in the laser beam was possible through this metalens. The rotation of birefringent droplets convinced that the optical trap possesses strong enough angular momentum of light from radiation of each nanostructure acting like a local half waveplate and introducing an orientation-dependent phase to light. Here, we show the success in creating a miniaturized and robust metalens based optical tweezers system capable of rotating liquid crystals droplets to imitate an optical motor for future lab-on-a-chip applications.</jats:p>}},
  author       = {{Suwannasopon, Satayu and Meyer, Fabian and Schlickriede, Christian and Chaisakul, Papichaya and T-Thienprasert, Jiraroj and Limtrakul, Jumras and Zentgraf, Thomas and Chattham, Nattaporn}},
  issn         = {{2073-4352}},
  journal      = {{Crystals}},
  number       = {{10}},
  pages        = {{515}},
  title        = {{{Miniaturized Metalens Based Optical Tweezers on Liquid Crystal Droplets for Lab-on-a-Chip Optical Motors}}},
  doi          = {{10.3390/cryst9100515}},
  volume       = {{9}},
  year         = {{2019}},
}

@article{13651,
  author       = {{Chen, Shumei and Reineke, Bernhard and Li, Guixin and Zentgraf, Thomas and Zhang, Shuang}},
  issn         = {{1530-6984}},
  journal      = {{Nano Letters}},
  number       = {{9}},
  pages        = {{6278--6283}},
  title        = {{{Strong Nonlinear Optical Activity Induced by Lattice Surface Modes on Plasmonic Metasurface}}},
  doi          = {{10.1021/acs.nanolett.9b02417}},
  volume       = {{19}},
  year         = {{2019}},
}

@article{13282,
  author       = {{Lin, Zemeng and Huang, Lingling and Xu, Zhen Tao and Li, Xiaowei and Zentgraf, Thomas and Wang, Yongtian}},
  issn         = {{2195-1071}},
  journal      = {{Advanced Optical Materials}},
  number       = {{21}},
  pages        = {{1900782}},
  title        = {{{Four‐Wave Mixing Holographic Multiplexing Based on Nonlinear Metasurfaces}}},
  doi          = {{10.1002/adom.201900782}},
  volume       = {{7}},
  year         = {{2019}},
}