Article
Physics, Applied
Poulab Chakrabarti, Faiha Mujeeb, Subhabrata Dhar
Summary: This study investigates the role of adsorbates and strain on the luminescence and polarization characteristics of large area monolayer MoS2. The removal of adsorbates from sulfur vacancy sites enhances the polarization and transferring the film to a new substrate improves the polarization and provides long lasting protection.
APPLIED PHYSICS LETTERS
(2022)
Article
Telecommunications
Keming Feng, Xiao Li, Yu Han, Shi Jin, Yijian Chen
Summary: This letter investigates the use of intelligent reflecting surfaces (IRS) to enhance the physical layer security of downlink wireless communication. The proposed algorithm jointly optimizes active and passive beamforming, achieving near optimal IRS phase shifts with fast convergence rate, almost reaching the performance upper bound.
IEEE COMMUNICATIONS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Xiaolei Ren, Yuehe Ge, Zhizhang David Chen, Hai Zhang
Summary: This article proposes a nonresonant partially reflecting surface (PRS) antenna that achieves high peak gain by using a transparent phase-correcting surface (PCS) for phase compensation. Theoretical analysis and numerical simulations demonstrate that the peak gain of the PRS antenna is maximized when the nonresonant cavity height is between 0.6 lambda and 0.9 lambda. Three prototypes are fabricated and tested, and the experimental results show that peak gains of over 25 dBi and 3 dB gain bandwidths of more than 10% can be achieved simultaneously.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Optics
Ting Zheng, Xianghong Niu, Hui Zhao, Jinlan Wang, Weiwei Zhao, Junpeng Lu, Zhenhua Ni
Summary: The introduction of a molecular state near the valence band into a MoS2 monolayer successfully increases the radiative states' density and accelerates exciton relaxation, leading to a drastic enhancement in photoluminescence (PL) efficiency under high power excitation levels.
Review
Chemistry, Multidisciplinary
Niko Hildebrandt, Mihye Lim, Namjun Kim, Da Yeon Choi, Jwa-Min Nam
Summary: Plasmonic metal nanoparticles and semiconductor quantum dots are widely used nanomaterials in optical biosensing and bioimaging. While their combination for fluorescence quenching via nanosurface energy transfer or Forster resonance energy transfer is common, metal-QD nanohybrids for plasmon-enhanced fluorescence have been less prevalent. This article discusses the challenges in optimizing distances, orientations, and spectral overlap for maximum plasmon-enhanced fluorescence and reviews the different nanomaterials, their combinations, and applications in advanced optical biosensing and bioimaging.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Xinyu Liu, Ziwei Ye, Qian Xiang, Zehong Xu, Wenhui Yue, Chunchun Li, Yikai Xu, Lingzhi Wang, Xiaoming Cao, Jinlong Zhang
Summary: Surface-enhanced Raman spectroscopy (SERS) is a powerful technique used in various research fields. Semiconductor SERS substrates, as alternatives to plasmonic metal substrates, have attractive attributes. However, they can only enhance the signals of analytes chemically adsorbed on their surface. In this study, we demonstrate the detection of non-adsorbing analytes on ZnO nanoparticles by coating them with ZIF-8 shells, which significantly enhances their electromagnetic enhancing capability and enables the detection of a wider range of non-adsorbing analytes.
Article
Optics
Mohamad Taghi Dejpasand, Esmaiel Saievar-Iranizad, Amir Bayat
Summary: Highly photoluminescent SLGQDs/Au nanocomposites were synthesized using a simple hydrothermal method, showing a novel cubic shape. Structural and optical properties were characterized through various techniques.
JOURNAL OF LUMINESCENCE
(2021)
Article
Chemistry, Multidisciplinary
Silan Wang, Qinzhen Li, Sha Yang, Haizhu Yu, Jinsong Chai, Manzhou Zhu
Summary: This study investigates the role of hydrogen bonding interactions in regulating the fluorescence properties of nanoclusters and demonstrates the importance of hydrogen bonds in this process through experiments.
Article
Chemistry, Physical
Hongping Xiang, Jiaxing Zu, Hongwei Jiang, Lin Xu, Gang Lu, Xu Zhang
Summary: Localized surface plasmon resonances in sodium nanorod dimers were systematically studied using quantum mechanical simulations. The size of the nanorods, their arrangement, and their gap distance were found to significantly affect the optical spectra, tunneling electric current, and electric field enhancement. Two plasmon resonant modes, one quantum in nature and the other electrostatic, were identified to be responsible for the observed electric field enhancement.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Review
Chemistry, Multidisciplinary
Dejing Meng, Tonghan Zhao, Dong Yang, Xue Jin, Pengfei Duan
Summary: Recently, there has been significant interest in the investigation of chiral materials exhibiting circularly polarized luminescence (CPL) due to their wide range of potential applications. However, it remains a challenge to find CPL-active molecules with both high luminescence dissymmetry factor (g(lum)) and emission efficiency (phi). Various strategies have been proposed to address this issue, but most systems suffer from a trade-off between g(lum) and phi. The local surface plasmonic resonance effect has shown promise in improving the overall performance of CPL, and this review provides a systematic summary of recent advancements in CPL-active plasmonic materials and offers perspective on their further development.
MATERIALS CHEMISTRY FRONTIERS
(2023)
Article
Nanoscience & Nanotechnology
O. Kulakovich, L. Gurinovich, Hui Li, A. Ramanenka, L. Trotsiuk, A. Muravitskaya, Jing Wei, Hongbo Li, N. Matveevskaya, D. Guzatov, S. Gaponenko
Summary: The study reports the impact of gold and silver plasmonic films on the photoluminescence and photostability of InP/ZnSe/ZnSeS/ZnS nanocrystals. Gold enhances photostability by reducing exciton lifetime, while silver reduces photostability without affecting photoluminescence intensity. Adjusting excitation wavelength and using a polyelectrolyte spacer can enhance luminescence intensity.
Article
Physics, Applied
Hanif Mohammadi, Ronel C. C. Roca, Yuwei Zhang, Hyunju Lee, Yoshio Ohshita, Naotaka Iwata, Itaru Kamiya
Summary: Ex situ low-temperature atomic layer deposition (ALD)-grown Al2O3 is used to passivate and enhance the photoluminescence (PL) of molecular beam epitaxy (MBE)-grown InAs surface quantum dots (SQDs). This is achieved without causing a significant PL blueshift observed in wet chemistry passivation and in situ GaAs capping by MBE. The Al2O3 cap layer retains the size and shape of the SQDs and allows for native oxide reduction.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Lukas Janos Richter, Juergen Ihlemann
Summary: Gold nanoparticles are incorporated into a silicon oxide matrix using excimer laser-based implantation to enhance the photoluminescence of silicon nanocrystals.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Engineering, Electrical & Electronic
Siyuan Weng, Man Zhao, Dayong Jiang
Summary: In this study, an organic/inorganic hybrid ultraviolet photodetector with outstanding photoelectric performance was fabricated. The heterojunction UV photodetector exhibited high responsivity, light-to-dark current ratio, external quantum efficiency, detectivity, and linear dynamic range. These findings provide new insights for the research and application of organic/inorganic hybrid UV photodetectors.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2022)
Article
Chemistry, Multidisciplinary
Yinzhou Yan, Xiaohua Zhang, Xiaoze Li, Honghua Fang, Yijian Jiang, Chen Zhao
Summary: A novel design is proposed to significantly enhance the degree of valley polarization (DoP) in ML-WSe2 by introducing Purcell effect and nanofocusing effect through a microsphere cavity array. The Purcell effect in the microcavity enhances the radiative decay rate, locking more polarized excitons in the corresponding valley. The nanofocusing effect increases the number of charged excitons by suppressing bright to dark exciton conversion. This study achieves a high DoP in ML-WSe2 with a simple configuration, promising broad applications in valleytronic devices and chiral optics in the future.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Haoran Ren, Stefan A. Maier
Summary: Twisted light, a helical spatial mode carrying orbital angular momentum, has great potential in optical and quantum information applications. However, current experiments are hindered by bulky, expensive, and slow-response optical elements. Nanophotonics offers a solution by providing compact and multifunctional devices for generating and detecting twisted light modes.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Lucca Kuehner, Luca Sortino, Benjamin Tilmann, Thomas Weber, Kenji Watanabe, Takashi Taniguchi, Stefan A. Maier, Andreas Tittl
Summary: All-dielectric optical metasurfaces with high-Q resonances throughout the visible spectrum have been achieved by leveraging symmetry-broken quasi bound states in the continuum (qBICs). These qBIC resonances effectively suppress radiation losses, allowing for the use of low-index van der Waals materials such as hexagonal boron nitride (hBN). The experimental results also demonstrated enhanced second-harmonic generation using the high-Q resonances.
ADVANCED MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Boris Kalinic, Tiziana Cesca, Ionut Gabriel Balasa, Mirko Trevisani, Andrea Jacassi, Stefan A. Maier, Riccardo Sapienza, Giovanni Mattei
Summary: In this study, we combine quasi-BIC modes with nanogaps in silicon slotted nanoantennas to enhance the electromagnetic local density of optical states (LDOS) in the optically active region. This leads to a significant boosting of photoluminescence intensity and decay rate of Er3+ emission. The nanoantenna directivity is also increased, showing strong beaming effects.
Article
Chemistry, Multidisciplinary
Luca M. Berger, Malo Duportal, Leonardo de Souza Menezes, Emiliano Cortes, Stefan A. Maier, Andreas Tittl, Katharina Krischer
Summary: Electrocatalysis is crucial for achieving a zero-carbon future and driving research in hydrogen generation and carbon dioxide reduction. Surface-enhanced infrared absorption spectroscopy (SEIRAS) is a suitable method for investigating electrocatalytic processes but has limitations in detecting short-lived intermediates. A new nanophotonic-electrochemical SEIRAS platform has been developed to overcome these limitations and provide a deeper understanding of catalytic reactions.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Allison R. Pessoa, Jefferson A. O. Galindo, Luiz F. dos Santos, Rogeria R. Goncalves, Stefan A. Maier, Leonardo de S. Menezes, Anderson M. Amaral
Summary: Lanthanide-doped single dielectric nanoparticles are used for nanoscale temperature sensing with high resolution. However, the low number of emitters in individual nanocrystals requires higher excitation power densities, which can cause overlapping emissions and affect temperature measurements. This study demonstrates a method to separate and correct these overlapping bands, resulting in improved temperature readout accuracy and corrected thermal artifacts.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Review
Optics
Andrea V. Bragas, Stefan A. Maier, Hilario D. Boggiano, Gustavo Grinblat, Rodrigo Bertc, Leonardo De S. Menezes, Emiliano Cortes
Summary: In this work, the physics of nanoresonators and their acoustic vibrations are reviewed, with frequencies in the range of a few to tens of GHz. Accurate determination of their oscillation frequencies allows them to act as mechanical nanoprobes, measuring local mechanical moduli and performing high-resolution imaging. The damping mechanisms and the role of the substrate are also discussed when nanoresonators are integrated into platforms and probed individually. The importance of manipulating hypersonic surface acoustic waves with nanoantennas and their potential applications in acousto-plasmonic devices operating in the GHz range and at nanoscale is also emphasized.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Tingting Lin, Tianyi Yang, Yuhang Cai, Jingwei Li, Guangxiang Lu, Shuangqun Chen, Yi Li, Liang Guo, Stefan A. Maier, Changxu Liu, Jianfeng Huang
Summary: Inspired by transformation optics, we propose a new concept for plasmonic photocatalysis by creating a novel hybrid nanostructure with a plasmonic singularity. Our geometry enables broad and strong spectral light harvesting at the active site of a nearby semiconductor where the chemical reaction occurs. The insights gained from this work might be beneficial for designing efficient composite plasmonic photocatalysts for diverse photocatalytic reactions.
Article
Chemistry, Multidisciplinary
Xiaofei Xiao, Raymond Gillibert, Antonino Foti, Pierre-Eugene Coulon, Christian Ulysse, Tadzio Levato, Stefan A. . Maier, Vincenzo Giannini, Pietro Giuseppe Gucciardi, Giancarlo Rizza
Summary: Surface-enhanced Raman optical activity (SEROA) has been extensively studied for its ability to directly probe the stereochemistry and molecular structure. This study presents a strategy for achieving a similar effect by coupling optically inactive molecules with the chiral plasmonic response of metasurfaces, resulting in a surface-enhanced Raman polarization rotation effect. This technique extends the potential of Raman optical activity to inactive molecules and enhances the sensitivity performances of surface-enhanced Raman spectroscopy, without the heating issue present in traditional plasmonic-enhanced ROA techniques.
Article
Chemistry, Multidisciplinary
Rodrigo Berte, Thomas Weber, Leonardo de Souza Menezes, Lucca Kuehner, Andreas Aigner, Martin Barkey, Fedja Jan Wendisch, Yuri Kivshar, Andreas Tittl, Stefan A. Maier
Summary: Breaking the in-plane geometric symmetry of dielectric metasurfaces allows access to a set of electromagnetic states called symmetry-protected quasi-bound states in the continuum (qBICs). We demonstrate that qBICs can also be accessed by breaking the symmetry in the permittivity of the materials. Weak permittivity modulations due to carrier doping, and electro-optical Pockels and Kerr effects, can enable infinitesimal permittivity asymmetries for on-demand, dynamically tunable resonances of extremely high quality factors.
Article
Chemistry, Physical
Thomas Weber, Lucca Kuehner, Luca Sortino, Amine Ben Mhenni, Nathan P. Wilson, Julius Kuehne, Jonathan J. Finley, Stefan A. Maier, Andreas Tittl
Summary: In this study, strong coupling in bound state in the continuum metasurfaces on nanostructured bulk WS2 is demonstrated, with sharp resonances, tailored linewidths, and controllable light-matter coupling strength.
Article
Physics, Multidisciplinary
Romain Tirole, Stefano Vezzoli, Emanuele Galiffi, Iain Robertson, Dries Maurice, Benjamin Tilmann, Stefan A. Maier, John B. Pendry, Riccardo Sapienza
Summary: A temporal version of Young's double-slit experiment shows interference in the frequency domain when light interacts with time slits produced by ultrafast changes in the refractive index.
Article
Chemistry, Multidisciplinary
Dmytro Gryb, Fedja J. Wendisch, Andreas Aigner, Thorsten Goelz, Andreas Tittl, Leonardo de S. Menezes, Stefan A. Maier
Summary: This study presents one of the geometrically simplest two-dimensional chiral metasurface platforms by arranging achiral dielectric rods in a square lattice and creating chirality through rotating individual meta-atoms. The chiroptical responses obtained from this design are stronger or comparable to more complex designs. Additionally, it is found that the resonances dependent on the arrangement are robust against geometric variations and exhibit similar behavior in experiments and simulations.
Article
Nanoscience & Nanotechnology
David A. Katzmarek, Andrea Mancini, Stefan A. Maier, Francesca Iacopi
Summary: This article presents a simple method for the direct synthesis of transfer-free, nanopatterned epitaxial graphene on silicon carbide on silicon substrates. By using common lithography and lift-off techniques, a catalytic alloy tailored for optimal SiC graphitization is patterned to form planar graphene structures on top of an unpatterned SiC layer. The method is compatible with both electron-beam lithography and UV-lithography, enabling the realization of graphene gratings with a minimum width/space of at least 100 nm at the wafer scale. The resolution is limited by the flow of the metal catalyst during the liquid-phase graphitization process, but it can be further improved through optimization of the metal deposition method and lift-off process.
Article
Optics
Lucca Kuehner, Fedja J. Wendisch, Alexander A. Antonov, Johannes Buerger, Ludwig Huettenhofer, Leonardo de S. Menezes, Stefan A. Maier, Maxim V. Gorkunov, Yuri Kivshar, Andreas Tittl
Summary: This research introduces a novel nanofabrication approach to effectively control resonance features and nanophotonic functionalities in all-dielectric metasurfaces by unlocking the height of individual resonators. Using this approach, an optical all-dielectric metasurface with maximum intrinsic chirality is demonstrated, which selectively responds to light of a particular circular polarization depending on the structural handedness.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Optics
Jisoo Kim, Johannes Buerger, Bumjoon Jang, Matthias Zeisberger, Julian Gargiulo, Leonardo de S. Menezes, Stefan A. Maier, Markus A. Schmidt
Summary: In this study, the properties of the on-chip hollow-core microgap waveguide in the context of optofluidics were investigated. The waveguide allows for intense light-water interaction and has fast response times. Various absorption-related experiments demonstrated the spectroscopic capabilities of the nanoprinted waveguide, and time-resolved experiments showed improved diffusion times due to the lateral access provided by the microgaps. Overall, the microgap waveguide represents a promising pathway for on-chip spectroscopy in aqueous environments.
