TY - JOUR AB - 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. AU - Hähnel, David AU - Golla, Christian AU - Albert, Maximilian AU - Zentgraf, Thomas AU - Myroshnychenko, Viktor AU - Förstner, Jens AU - Meier, Cedrik ID - 44097 IS - 1 JF - Light: Science & Applications KW - tet_topic_meta SN - 2047-7538 TI - A multi-mode super-fano mechanism for enhanced third harmonic generation in silicon metasurfaces VL - 12 ER - TY - JOUR AU - Widhalm, Alex AU - Golla, Christian AU - Weber, Nils AU - Mackwitz, Peter AU - Zrenner, Artur AU - Meier, Cedrik ID - 29716 IS - 4 JF - Optics Express KW - Atomic and Molecular Physics KW - and Optics SN - 1094-4087 TI - Electric-field-induced second harmonic generation in silicon dioxide VL - 30 ER - TY - JOUR AB - The free exciton transition (near-band-edge emission, NBE) of ZnO at ≈388 nm can be strongly enhanced and even stimulated by an underlying photonic structure. 1D Photonic crystals, so-called distributed Bragg reflectors, are utilized to suppress the deep-level emission of ZnO (DLE, ≈500–530 nm). The reflector stacks are fabricated in a layer-by-layer procedure by wet-chemical synthesis. They consist of low-ε porous SiO2 layers and high-ε TiO2 layers. Varying the thickness of the SiO2 layers allows tuning the optical bandgap in a wide range between ≈420 and 800 nm. A ZnO layer is deposited on top of the reflector stacks by sol–gel synthesis. The spontaneous photoluminescence (PL) emission of the ZnO film is modulated by the photonic structure. When the optical bandgap of the reflector is in resonance with the deep-level emission of ZnO (DLE, ≈500–530 nm), then this defect-related emission mode is suppressed. Strong NBE emission is observed even when the ZnO layer does not show any NBE emission (due to low crystallinity) in the absence of the photonic structure. With this cost-efficient synthesis method, emitters for, e.g., luminescent gas sensors can be fabricated. AU - Kothe, Linda AU - Albert, Maximilian AU - Meier, Cedrik AU - Wagner, Thorsten AU - Tiemann, Michael ID - 29790 JF - Advanced Materials Interfaces KW - Mechanical Engineering KW - Mechanics of Materials SN - 2196-7350 TI - Stimulation and Enhancement of Near‐Band‐Edge Emission in Zinc Oxide by Distributed Bragg Reflectors ER - TY - JOUR AB - Lithium niobate on insulator (LNOI) has a great potential for photonic integrated circuits, providing substantial versatility in design of various integrated components. To properly use these components in the implementation of different quantum protocols, photons with different properties are required. In this paper, we theoretically demonstrate a flexible source of correlated photons built on the LNOI waveguide of a special geometry. This source is based on the parametric down-conversion (PDC) process, in which the signal and idler photons are generated at the telecom wavelength and have different spatial profiles and polarizations, but the same group velocities. Distinguishability in polarizations and spatial profiles facilitates the routing and manipulating individual photons, while the equality of their group velocities leads to the absence of temporal walk-off between photons. We show how the spectral properties of the generated photons and the number of their frequency modes can be controlled depending on the pump characteristics and the waveguide length. Finally, we discuss special regimes, in which narrowband light with strong frequency correlations and polarization-entangled Bell states are generated at the telecom wavelength. AU - Ebers, Lena AU - Ferreri, Alessandro AU - Hammer, Manfred AU - Albert, Maximilian AU - Meier, Cedrik AU - Förstner, Jens AU - Sharapova, Polina R. ID - 30210 JF - Journal of Physics: Photonics KW - tet_topic_waveguide SN - 2515-7647 TI - Flexible source of correlated photons based on LNOI rib waveguides VL - 4 ER - TY - JOUR AB - In this paper, silicon oxynitride films (SiON) grown by plasma-enhanced chemical vapor deposition are investigated. As precursor gases silane (SiH4), nitrous oxide (N2O), nitrogen (N2) and ammonia (NH3) are used with different compositions. We find that for achieving high nitrogen content adding ammonia to the precursor mix is most efficient. Moreover, we investigate the balance between adsorption and desorption processes during film growth by investigating the film growth rate as a function of the substrate temperature. From these data we are able to determine an effective activation energy for the film growth, corresponding to the difference between adsorption and desorption energy. Finally, we have thoroughly investigated the optical properties of the films using spectroscopic ellipsometry. From these measurements, we suggest a parametrized model for the refractive index and extinction coefficient in a wide range of compositions based on a Cauchy- and a Lorentz-fit. AU - Aschwanden, R. AU - Köthemann, R. AU - Albert, M. AU - Golla, C. AU - Meier, Cedrik ID - 23815 JF - Thin Solid Films SN - 0040-6090 TI - Optical properties of silicon oxynitride films grown by plasma-enhanced chemical vapor deposition VL - 736 ER - TY - JOUR AB - GaAs-(111)-nanostructures exhibiting second harmonic generation are new building blocks in nonlinear optics. Such structures can be fabricated through epitaxial lift-off using selective etching of Al-containing layers and subsequent transfer to glass substrates. Herein, the selective etching of (111)B-oriented AlxGa1−xAs sacrificial layers (10–50 nm thick) with different aluminum concentrations (x = 0.5–1.0) in 10\% hydrofluoric acid is investigated and compared with standard (100)-oriented structures. The thinner the sacrificial layer and the lower the aluminum content, the lower the lateral etch rate. For both orientations, the lateral etch rates are in the same order of magnitude, but some quantitative differences exist. Furthermore, the epitaxial lift-off, the transfer, and the nanopatterning of thin (111)B-oriented GaAs membranes are demonstrated. Atomic force microscopy and high-resolution X-ray diffraction measurements reveal the high structural quality of the transferred GaAs-(111) films. AU - Henksmeier, Tobias AU - Eppinger, Martin AU - Reineke, Bernhard AU - Zentgraf, Thomas AU - Meier, Cedrik AU - Reuter, Dirk ID - 20592 IS - 3 JF - physica status solidi (a) KW - epitaxial lift-off KW - GaAs/AlxGa1−xAs heterostructures KW - selective etching TI - Selective Etching of (111)B-Oriented AlxGa1−xAs-Layers for Epitaxial Lift-Off VL - 218 ER - TY - JOUR AU - Albert, M. AU - Golla, C. AU - Meier, Cedrik ID - 20900 JF - Journal of Crystal Growth SN - 0022-0248 TI - Optical in-situ temperature management for high-quality ZnO molecular beam epitaxy VL - 557 ER - TY - JOUR AU - Mund, Johannes AU - Yakovlev, Dmitri R. AU - Sadofev, Sergey AU - Meier, Cedrik AU - Bayer, Manfred ID - 22214 JF - Physical Review B SN - 2469-9950 TI - Second harmonic generation on excitons in ZnO/(Zn,Mg)O quantum wells with built-in electric fields VL - 103 ER - TY - JOUR AB - Plasmonic nanoantennas for visible and infrared radiation strongly improve the interaction of light with the matter on the nanoscale due to their strong near-field enhancement. In this study, we investigate a double-resonant plasmonic nanoantenna, which makes use of plasmonic field enhancement, enhanced outcoupling of second harmonic light, and resonant lattice effects. Using this design, we demonstrate how the efficiency of second harmonic generation can be increased significantly by fully embedding the nanoantennas into nonlinear dielectric material ZnO, instead of placing them on the surface. Investigating two different processes, we found that the best fabrication route is embedding the gold nanoantennas in ZnO using an MBE overgrowth process where a thin ZnO layer was deposited on nanoantennas fabricated on a ZnO substrate. In addition, second harmonic generation measurements show that the embedding leads to an enhancement compared to the emission of nanoantennas placed on the ZnO substrate surface. These promising results facilitate further research to determine the influence of the periodicity of the nanoantenna arrangement of the resulting SHG signal. AU - Volmert, Ruth AU - Weber, Nils AU - Meier, Cedrik ID - 20644 IS - 4 JF - Journal of Applied Physics SN - 0021-8979 TI - Nanoantennas embedded in zinc oxide for second harmonic generation enhancement VL - 128 ER - TY - JOUR AB - 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. AU - Liu, Bingyi AU - Sain, Basudeb AU - Reineke, Bernhard AU - Zhao, Ruizhe AU - Meier, Cedrik AU - Huang, Lingling AU - Jiang, Yongyuan AU - Zentgraf, Thomas ID - 16197 IS - 9 JF - Advanced Optical Materials SN - 2195-1071 TI - Nonlinear Wavefront Control by Geometric-Phase Dielectric Metasurfaces: Influence of Mode Field and Rotational Symmetry VL - 8 ER - TY - CONF AB - We fabricate silicon tapers to increase the mode overlap of superconducting detectors on Ti:LiNbO3 waveguides. Mode images show a reduction in mode size from 6 µm to 2 µm FWHM, agreeing with beam propagation simulations. AU - Protte, Maximilian AU - Ebers, Lena AU - Hammer, Manfred AU - Höpker, Jan Philipp AU - Albert, Maximilian AU - Quiring, Viktor AU - Meier, Cedrik AU - Förstner, Jens AU - Silberhorn, Christine AU - Bartley, Tim ID - 21719 KW - tet_topic_waveguide SN - 9781943580811 T2 - OSA Quantum 2.0 Conference TI - Towards Semiconductor-Superconductor-Crystal Hybrid Integration for Quantum Photonics ER - TY - JOUR AB - 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. AU - Sain, Basudeb AU - Meier, Cedrik AU - Zentgraf, Thomas ID - 8797 IS - 2 JF - Advanced Photonics SN - 2577-5421 TI - Nonlinear optics in all-dielectric nanoantennas and metasurfaces: a review VL - 1 ER - TY - JOUR AU - Golla, C. AU - Weber, N. AU - Meier, Cedrik ID - 9698 IS - 7 JF - Journal of Applied Physics SN - 0021-8979 TI - Zinc oxide based dielectric nanoantennas for efficient nonlinear frequency conversion VL - 125 ER - TY - JOUR AU - Protte, Maximilian AU - Weber, Nils AU - Golla, Christian AU - Zentgraf, Thomas AU - Meier, Cedrik ID - 9897 JF - Journal of Applied Physics SN - 0021-8979 TI - Strong nonlinear optical response from ZnO by coupled and lattice-matched nanoantennas VL - 125 ER - TY - JOUR AU - Köthemann, Ronja AU - Weber, Nils AU - Lindner, Jörg K N AU - Meier, Cedrik ID - 12930 IS - 9 JF - Semiconductor Science and Technology SN - 0268-1242 TI - High-precision determination of silicon nanocrystals: optical spectroscopy versus electron microscopy VL - 34 ER - TY - JOUR AU - Vondran, J. AU - Spitzer, F. AU - Bayer, M. AU - Akimov, I. A. AU - Trautmann, Alexander AU - Reichelt, Matthias AU - Meier, Cedrik AU - Weber, N. AU - Meier, Torsten AU - André, R. AU - Mariette, H. ID - 14544 IS - 15 JF - Physical Review B SN - 2469-9950 TI - Spatially asymmetric transients of propagating exciton-polariton modes in a planar CdZnTe/CdMgTe guiding structure VL - 100 ER - TY - JOUR AU - Vondran, J. AU - Spitzer, F. AU - Bayer, M. AU - Akimov, I. A. AU - Trautmann, Alexander AU - Reichelt, Matthias AU - Meier, Cedrik AU - Weber, N. AU - Meier, Torsten AU - André, R. AU - Mariette, H. ID - 22887 IS - 15 JF - Physical Review B SN - 2469-9950 TI - Spatially asymmetric transients of propagating exciton-polariton modes in a planar CdZnTe/CdMgTe guiding structure VL - 100 ER - TY - JOUR AU - Hoffmann, Sandro P. AU - Albert, Maximilian AU - Weber, Nils AU - Sievers, Denis AU - Förstner, Jens AU - Zentgraf, Thomas AU - Meier, Cedrik ID - 1430 JF - ACS Photonics KW - tet_topic_phc SN - 2330-4022 TI - Tailored UV Emission by Nonlinear IR Excitation from ZnO Photonic Crystal Nanocavities VL - 5 ER - TY - JOUR AU - Weber, N. AU - Hoffmann, S. P. AU - Albert, M. AU - Zentgraf, Thomas AU - Meier, Cedrik ID - 1327 IS - 10 JF - Journal of Applied Physics SN - 0021-8979 TI - Efficient frequency conversion by combined photonic–plasmonic mode coupling VL - 123 ER - TY - JOUR AB - The electronic band structures of hexagonal ZnO and cubic ZnS, ZnSe, and ZnTe compounds are determined within hybrid-density-functional theory and quasiparticle calculations. It is found that the band-edge energies calculated on the G0W0 (Zn chalcogenides) or GW (ZnO) level of theory agree well with experiment, while fully self-consistent QSGW calculations are required for the correct description of the Zn 3d bands. The quasiparticle band structures are used to calculate the linear response and second-harmonic-generation (SHG) spectra of the Zn–VI compounds. Excitonic effects in the optical absorption are accounted for within the Bethe–Salpeter approach. The calculated spectra are discussed in the context of previous experimental data and present SHG measurements for ZnO. AU - Riefer, Arthur AU - Weber, Nils AU - Mund, Johannes AU - Yakovlev, Dmitri R. AU - Bayer, Manfred AU - Schindlmayr, Arno AU - Meier, Cedrik AU - Schmidt, Wolf Gero ID - 7481 IS - 21 JF - Journal of Physics: Condensed Matter SN - 0953-8984 TI - Zn–VI quasiparticle gaps and optical spectra from many-body calculations VL - 29 ER -