@article{32068, abstract = {{Inspired by plant grafting, grafted vortex beams can be formed through grafting two or more helical phase profiles of optical vortex beams. Recently, grafted perfect vortex beams (GPVBs) have attracted much attention due to their unique optical properties and potential applications. However, the current method to generate and manipulate GPVBs requires a complex and bulky optical system, hindering further investigation and limiting its practical applications. Here, a compact metasurface approach for generating and manipulating GPVBs in multiple channels is proposed and demonstrated, which eliminates the need for such a complex optical setup. A single metasurface is utilized to realize various superpositions of GPVBs with different combinations of topological charges in four channels, leading to asymmetric singularity distributions. The positions of singularities in the superimposed beam can be further modulated by introducing an initial phase difference in the metasurface design. The work demonstrates a compact metasurface platform that performs a sophisticated optical task that is very challenging with conventional optics, opening opportunities for the investigation and applications of GPVBs in a wide range of emerging application areas, such as singular optics and quantum science.}}, author = {{Ahmed, Hammad and Intaravanne, Yuttana and Ming, Yang and Ansari, Muhammad Afnan and Buller, Gerald S. and Zentgraf, Thomas and Chen, Xianzhong}}, issn = {{0935-9648}}, journal = {{Advanced Materials}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, number = {{30}}, publisher = {{Wiley}}, title = {{{Multichannel Superposition of Grafted Perfect Vortex Beams}}}, doi = {{10.1002/adma.202203044}}, volume = {{34}}, year = {{2022}}, } @inproceedings{34238, abstract = {{A monolithically integrated electronic-photonic Mach-Zehnder modulator is presented, incorporating electronic linear drivers along photonic components. An electro-optical 3 dB & 6 dB bandwidth of 24 GHz and 34 GHz respectively was measured. The on-chip drivers decrease the V π by a factor of 10.}}, author = {{Kress, Christian and Schwabe, Tobias and Rhee, Hanjo and Kerman, Sarp and Scheytt, J. Christoph}}, booktitle = {{Optica Advanced Photonics Congress 2022}}, publisher = {{Optica Publishing Group}}, title = {{{Broadband Mach-Zehnder Modulator with Linear Driver in Electronic-Photonic Co-Integrated Platform}}}, doi = {{10.1364/iprsn.2022.im4c.1}}, year = {{2022}}, } @inproceedings{46484, abstract = {{Efficient third-harmonic generation control is theoretically studied. Dielectric nanostructures placed on the metallic substrate could offer effective geometric-phase modulation on third-harmonic signals by selecting proper structure rotational symmetry.}}, author = {{Liu, Bingyi and Huang, Lingling and Zentgraf, Thomas}}, booktitle = {{Conference on Lasers and Electro-Optics}}, location = {{San Jose, USA}}, publisher = {{Optica Publishing Group}}, title = {{{Efficient Third-harmonic Generation Control with Ultrathin Dielectric Geometric-phase Metasurface}}}, doi = {{10.1364/cleo_qels.2022.fth1a.7}}, 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}}, } @article{32310, author = {{Li, Yao and Ma, Xuekai and Zhai, Xiaokun and Gao, Meini and Dai, Haitao and Schumacher, Stefan and Gao, Tingge}}, 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 = {{{Manipulating polariton condensates by Rashba-Dresselhaus coupling at room temperature}}}, doi = {{10.1038/s41467-022-31529-4}}, volume = {{13}}, year = {{2022}}, } @inproceedings{41800, author = {{Sartison, M and Camacho Ibarra, O and Jöns, Klaus D. and Caltzidis, I and Reuter, Dirk}}, title = {{{Scalable integration of quantum emitters into photonic integrated circuits}}}, doi = {{https://doi.org/10.1088/2633-4356/ac6f3e}}, volume = {{2}}, year = {{2022}}, } @article{33670, author = {{Schapeler, Timon and Bartley, Tim}}, issn = {{2469-9926}}, journal = {{Physical Review A}}, number = {{1}}, publisher = {{American Physical Society (APS)}}, title = {{{Information extraction in photon-counting experiments}}}, doi = {{10.1103/physreva.106.013701}}, volume = {{106}}, year = {{2022}}, } @inproceedings{63039, abstract = {{We report on coherent transmission of beyond 100 GBd signaling based on plasmonic technology. Using dual-drive plasmonic-organic-hybrid I/Q modulator on silicon photonics platform, we demonstrate the successful transmission of 160-GBaud QPSK and 140-GBaud 16QAM modulations.}}, author = {{Mardoyan, Haïk and Jorge, Filipe and Destraz, Marcel and Duval, Bernadette and Bitachon, Bertold and Horst, Yannik and Benyahya, Kaoutar and Blache, Fabrice and Goix, Michel and De Leo, Eva and Habegger, Patrick and Meier, Norbert and Del Medico, Nino and Tedaldi, Valentino and Funck, Christian and Güsken, Nicholas Alexander and Leuthold, Juerg and Renaudier, Jéremie and Hoessbacher, Claudia and Heni, Wolfgang and Baeuerle, Benedikt}}, booktitle = {{Optical Fiber Communication Conference (OFC) 2022}}, publisher = {{Optica Publishing Group}}, title = {{{Generation and transmission of 160-Gbaud QPSK Coherent Signals using a Dual-Drive Plasmonic-Organic Hybrid I/Q modulator on Silicon Photonics}}}, doi = {{10.1364/ofc.2022.th1j.5}}, year = {{2022}}, } @inproceedings{63041, author = {{Güsken, Nicholas Alexander}}, publisher = {{Optica Publishing Group}}, title = {{{Plasmonic PICs—Terabit Modulation on the Micrometer Scale}}}, doi = {{https://opg.optica.org/abstract.cfm?URI=ECEOC-2022-Tu4E.3}}, year = {{2022}}, } @article{30921, abstract = {{Quantum walks function as essential means to implement quantum simulators, allowing one to study complex and often directly inaccessible quantum processes in controllable systems. In this contribution, the notion of a driven Gaussian quantum walk is introduced. In contrast to typically considered quantum walks in optical settings, we describe the operation of the walk in terms of a nonlinear map rather than a unitary operation, e.g., by replacing a beam-splitter-type coin with a two-mode squeezer, being a process that is controlled and driven by a pump field. This opens previously unattainable possibilities for quantum walks that include nonlinear elements as core components of their operation, vastly extending their range of applications. A full framework for driven Gaussian quantum walks is developed, including methods to dynamically characterize nonlinear, quantum, and quantum-nonlinear effects. Moreover, driven Gaussian quantum walks are compared with their classically interfering and linear counterparts, which are based on classical coherence of light rather than quantum superpositions. In particular, the generation and boost of highly multimode entanglement, squeezing, and other quantum effects are studied over the duration of the nonlinear walk. Importantly, we prove the quantumness of the evolution itself, regardless of the input state. A scheme for an experimental realization is proposed. Furthermore, nonlinear properties of driven Gaussian quantum walks are explored, such as amplification that leads to an ever increasing number of correlated quantum particles, constituting a source of new walkers during the walk. Therefore, a concept for quantum walks is proposed that leads to—and even produces—directly accessible quantum phenomena, and that renders the quantum simulation of nonlinear processes possible.}}, author = {{Held, Philip and Engelkemeier, Melanie and De, Syamsundar and Barkhofen, Sonja and Sperling, Jan and Silberhorn, Christine}}, issn = {{2469-9926}}, journal = {{Physical Review A}}, number = {{4}}, publisher = {{American Physical Society (APS)}}, title = {{{Driven Gaussian quantum walks}}}, doi = {{10.1103/physreva.105.042210}}, volume = {{105}}, year = {{2022}}, } @inproceedings{27160, abstract = {{We study the complexity of problems solvable in deterministic polynomial time with access to an NP or Quantum Merlin-Arthur (QMA)-oracle, such as $P^{NP}$ and $P^{QMA}$, respectively. The former allows one to classify problems more finely than the Polynomial-Time Hierarchy (PH), whereas the latter characterizes physically motivated problems such as Approximate Simulation (APX-SIM) [Ambainis, CCC 2014]. In this area, a central role has been played by the classes $P^{NP[\log]}$ and $P^{QMA[\log]}$, defined identically to $P^{NP}$ and $P^{QMA}$, except that only logarithmically many oracle queries are allowed. Here, [Gottlob, FOCS 1993] showed that if the adaptive queries made by a $P^{NP}$ machine have a "query graph" which is a tree, then this computation can be simulated in $P^{NP[\log]}$. In this work, we first show that for any verification class $C\in\{NP,MA,QCMA,QMA,QMA(2),NEXP,QMA_{\exp}\}$, any $P^C$ machine with a query graph of "separator number" $s$ can be simulated using deterministic time $\exp(s\log n)$ and $s\log n$ queries to a $C$-oracle. When $s\in O(1)$ (which includes the case of $O(1)$-treewidth, and thus also of trees), this gives an upper bound of $P^{C[\log]}$, and when $s\in O(\log^k(n))$, this yields bound $QP^{C[\log^{k+1}]}$ (QP meaning quasi-polynomial time). We next show how to combine Gottlob's "admissible-weighting function" framework with the "flag-qubit" framework of [Watson, Bausch, Gharibian, 2020], obtaining a unified approach for embedding $P^C$ computations directly into APX-SIM instances in a black-box fashion. Finally, we formalize a simple no-go statement about polynomials (c.f. [Krentel, STOC 1986]): Given a multi-linear polynomial $p$ specified via an arithmetic circuit, if one can "weakly compress" $p$ so that its optimal value requires $m$ bits to represent, then $P^{NP}$ can be decided with only $m$ queries to an NP-oracle.}}, author = {{Gharibian, Sevag and Rudolph, Dorian}}, booktitle = {{13th Innovations in Theoretical Computer Science (ITCS 2022)}}, number = {{75}}, pages = {{1--27}}, title = {{{On polynomially many queries to NP or QMA oracles}}}, doi = {{10.4230/LIPIcs.ITCS.2022.75}}, volume = {{215}}, year = {{2022}}, } @article{21631, abstract = {{Secret sharing is a well-established cryptographic primitive for storing highly sensitive information like encryption keys for encoded data. It describes the problem of splitting a secret into different shares, without revealing any information to its shareholders. Here, we demonstrate an all-optical solution for secret sharing based on metasurface holography. In our concept, metasurface holograms are used as spatially separable shares that carry encrypted messages in the form of holographic images. Two of these shares can be recombined by bringing them close together. Light passing through this stack of metasurfaces accumulates the phase shift of both holograms and optically reconstructs the secret with high fidelity. In addition, the hologram generated by each single metasurface can uniquely identify its shareholder. Furthermore, we demonstrate that the inherent translational alignment sensitivity between two stacked metasurface holograms can be used for spatial multiplexing, which can be further extended to realize optical rulers.}}, author = {{Georgi, Philip and Wei, Qunshuo and Sain, Basudeb and Schlickriede, Christian and Wang, Yongtian and Huang, Lingling and Zentgraf, Thomas}}, issn = {{2375-2548}}, journal = {{Science Advances}}, number = {{16}}, title = {{{Optical secret sharing with cascaded metasurface holography}}}, doi = {{10.1126/sciadv.abf9718}}, volume = {{7}}, year = {{2021}}, } @article{28255, abstract = {{Topological photonic crystals (TPhCs) provide robust manipulation of light with built-in immunity to fabrication tolerances and disorder. Recently, it was shown that TPhCs based on weak topology with a dislocation inherit this robustness and further host topologically protected lower-dimensional localized modes. However, TPhCs with weak topology at optical frequencies have not been demonstrated so far. Here, we use scattering-type scanning near-field optical microscopy to verify mid-bandgap zero-dimensional light localization close to 100 THz in a TPhC with nontrivial Zak phase and an edge dislocation. We show that because of the weak topology, differently extended dislocation centers induce similarly strong light localization. The experimental results are supported by full-field simulations. Along with the underlying fundamental physics, our results lay a foundation for the application of TPhCs based on weak topology in active topological nanophotonics, and nonlinear and quantum optic integrated devices because of their strong and robust light localization.}}, author = {{Lu, Jinlong and Wirth, Konstantin G. and Gao, Wenlong and Heßler, Andreas and Sain, Basudeb and Taubner, Thomas and Zentgraf, Thomas}}, issn = {{2375-2548}}, journal = {{Science Advances}}, number = {{49}}, title = {{{Observing 0D subwavelength-localized modes at ~100 THz protected by weak topology}}}, doi = {{10.1126/sciadv.abl3903}}, volume = {{7}}, year = {{2021}}, } @article{31261, abstract = {{Abstract For a compact Riemannian locally symmetric space $\mathcal M$ of rank 1 and an associated vector bundle $\mathbf V_{\tau }$ over the unit cosphere bundle $S^{\ast }\mathcal M$, we give a precise description of those classical (Pollicott–Ruelle) resonant states on $\mathbf V_{\tau }$ that vanish under covariant derivatives in the Anosov-unstable directions of the chaotic geodesic flow on $S^{\ast }\mathcal M$. In particular, we show that they are isomorphically mapped by natural pushforwards into generalized common eigenspaces of the algebra of invariant differential operators $D(G,\sigma )$ on compatible associated vector bundles $\mathbf W_{\sigma }$ over $\mathcal M$. As a consequence of this description, we obtain an exact band structure of the Pollicott–Ruelle spectrum. Further, under some mild assumptions on the representations $\tau$ and $\sigma$ defining the bundles $\mathbf V_{\tau }$ and $\mathbf W_{\sigma }$, we obtain a very explicit description of the generalized common eigenspaces. This allows us to relate classical Pollicott–Ruelle resonances to quantum eigenvalues of a Laplacian in a suitable Hilbert space of sections of $\mathbf W_{\sigma }$. Our methods of proof are based on representation theory and Lie theory.}}, author = {{Küster, Benjamin and Weich, Tobias}}, issn = {{1073-7928}}, journal = {{International Mathematics Research Notices}}, keywords = {{General Mathematics}}, number = {{11}}, pages = {{8225--8296}}, publisher = {{Oxford University Press (OUP)}}, title = {{{Quantum-Classical Correspondence on Associated Vector Bundles Over Locally Symmetric Spaces}}}, doi = {{10.1093/imrn/rnz068}}, volume = {{2021}}, year = {{2021}}, } @article{29524, author = {{De, Syamsundar and Gil López, Jano and Brecht, Benjamin and Silberhorn, Christine and Sánchez-Soto, Luis L. and Hradil, Zdeněk and Řeháček, Jaroslav}}, issn = {{2643-1564}}, journal = {{Physical Review Research}}, keywords = {{General Engineering}}, number = {{3}}, publisher = {{American Physical Society (APS)}}, title = {{{Effects of coherence on temporal resolution}}}, doi = {{10.1103/physrevresearch.3.033082}}, volume = {{3}}, year = {{2021}}, } @article{22259, author = {{Roman-Rodriguez, V and Brecht, Benjamin and Srinivasan, K and Silberhorn, Christine and Treps, N and Diamanti, E and Parigi, V}}, issn = {{1367-2630}}, journal = {{New Journal of Physics}}, title = {{{Continuous variable multimode quantum states via symmetric group velocity matching}}}, doi = {{10.1088/1367-2630/abef96}}, volume = {{23}}, year = {{2021}}, } @article{31263, author = {{Guillarmou, Colin and Hilgert, Joachim and Weich, Tobias}}, issn = {{2644-9463}}, journal = {{Annales Henri Lebesgue}}, pages = {{81--119}}, publisher = {{Cellule MathDoc/CEDRAM}}, title = {{{High frequency limits for invariant Ruelle densities}}}, doi = {{10.5802/ahl.67}}, volume = {{4}}, year = {{2021}}, } @misc{38135, author = {{Padberg, Laura and Eigner, Christof and Santandrea, Matteo and Silberhorn, Christine}}, title = {{{Production of waveguides made of materials from the KTP family}}}, year = {{2021}}, } @article{37936, author = {{Pelucchi, Emanuele and Fagas, Giorgos and Aharonovich, Igor and Englund, Dirk and Figueroa, Eden and Gong, Qihuang and Hannes, Hübel and Liu, Jin and Lu, Chao-Yang and Matsuda, Nobuyuki and Pan, Jian-Wei and Schreck, Florian and Sciarrino, Fabio and Silberhorn, Christine and Wang, Jianwei and Jöns, Klaus}}, issn = {{2522-5820}}, journal = {{Nature Reviews Physics}}, keywords = {{General Physics and Astronomy}}, number = {{3}}, pages = {{194--208}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{The potential and global outlook of integrated photonics for quantum technologies}}}, doi = {{10.1038/s42254-021-00398-z}}, volume = {{4}}, year = {{2021}}, } @article{22770, author = {{Gil López, Jano and Santandrea, Matteo and Roland, Ganaël and Brecht, Benjamin and Eigner, Christof and Ricken, Raimund and Quiring, Viktor and Silberhorn, Christine}}, issn = {{1367-2630}}, journal = {{New Journal of Physics}}, title = {{{Improved non-linear devices for quantum applications}}}, doi = {{10.1088/1367-2630/ac09fd}}, year = {{2021}}, }