Article
Optics
Vladimir I. Korobov, D. Bakalov
Summary: We systematically calculate the forbidden electric dipole transitions in the homonuclear molecular ion H-2(+). The transition rate from the ground ortho state to the ground para state is found to be 4.9 x 10(-14) s(-1), corresponding to a lifetime of 6.4 x 10(5) yr. The Einstein coefficient A(nn) for the transition from state (v =1, N =1, J =1/2) to (v =0, N =0, J =1/2) is determined to be 0.12 x 10(-9) s(-1), which is comparable to the values for quadrupole transitions in H-2(+). This suggests that ortho-para transitions in H-2(+) can be explored using laser spectroscopy.
Article
Chemistry, Multidisciplinary
Da-Jie Yang, Ji-Cai Liu
Summary: In this study, efficient and selective high-order resonances were demonstrated in symmetric and asymmetric plasmonic nanoparticles using vortex beams. A pure high-order resonance was observed in symmetric nanoparticles configured with a complete nanoring lying on the focal center. Asymmetric nanoparticles configured with a complete ring off the beam center or a splitting nanoring showed multiple resonances influenced by the ring's geometry, position, orientation, and photon OAM. These findings contribute to the understanding and control of OAM-involved light-material interactions in asymmetric nanosystems.
Article
Chemistry, Multidisciplinary
Da-Jie Yang, Song-Jin Im, Yang Li, Chol-Song Ri, Kum-Song Ho, Ji-Song Pae, Qu-Quan Wang
Summary: This study provides insights into the complex plasmon behaviors with the physical dimension of orbital angular momentum (OAM) and proves that plasmonic nanostructures can function as efficient antennas to control the power of OAM beams. These findings expand our knowledge of nanoplasmonics in the OAM area and have promising applications in quantum information processing and dynamic sensing of ultraweak biosignals.
Article
Optics
Jingying Miao, Shencheng Fu, Xin Li, Hongfang Liu, Xintong Zhang, Haiyang Xu, Yichun Liu
Summary: Holography is used as a feasible method for information encryption, and a serial coding system based on a plasmonic holographic disk utilizing the spin and orbital angular momenta of photons is designed. The accurate distinction of the polarization state and topological charge of the vortex light field enables stable readout of the encrypted holographic grating array.
Article
Optics
Xiang-Yu Zeng, Yu-Qin Zhang, Rui-Rui Zhang, Xiao-Rong Ren, Zi-Jun Zhan, Man-Na Gu, Rui Sun, Chun-Xiang Liu, Chuan-Fu Cheng
Summary: Metasurfaces with orthogonal nano-slit pairs arranged on spirals are proposed to generate vector beams of Bell-like states and slanted polarizations. The design is based on the theoretically derived parameter condition for manipulation of the two vector vortex modes, satisfied by matching the rotation order m, the spiral order n, and incident polarization helicity sigma. Linear polarization states of the vector beams are controlled by the initial orientation angle of slit pairs.
Article
Chemistry, Multidisciplinary
Eva Prinz, Grisha Spektor, Michael Hartelt, Anna-Katharina Mahro, Martin Aeschlimann, Meir Orenstein
Summary: By tailoring the local and global geometries of vortex generators, arbitrary switching in the delivered plasmonic angular momentum can be achieved, providing a new method for plasmonic manipulation. The precise control over the generation and rotation direction of high-order plasmonic vortices was demonstrated, as well as the capability to create complex topological fields.
Article
Physics, Applied
Qiao Jiang, Hong Xiang, Dezhuan Han
Summary: This study proposes a method to design a plasmonic metasurface that can control the generation and superposition of surface plasmon polariton (SPP) vortices, demonstrating that the superposition of SPP vortices can be accurately controlled by the polarization states of the incidence, providing a feasible way to design miniaturized photonic devices.
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Multidisciplinary
Stephen M. Barnett, Fiona C. Speirits, Mohamed Babiker
Summary: In summary, this paradox questions how a Gaussian beam, which has zero orbital angular momentum, can drive a quadrupole transition that requires the transfer of angular momentum to an absorbing atom.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Article
Engineering, Electrical & Electronic
Geng-Bo Wu, Ka Fai Chan, Kam Man Shum, Chi Hou Chan
Summary: This article introduces a flat lens antenna capable of OAM mode multiplexing, designed using holographic theory and special transmit elements to achieve broadband performance. Experimental validation shows that the antenna can successfully demonstrate OAM mode multiplexing, indicating promising potential for high-speed millimeter-wave communication applications.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Nanoscience & Nanotechnology
Masoud Taleb, Mohsen Samadi, Fatemeh Davoodi, Maximilian Black, Janek Buhl, Hannes Lueder, Martina Gerken, Nahid Talebi
Summary: The study of spin-orbit coupling (SOC) of light is crucial to explore the light-matter interactions in sub-wavelength structures. By designing a plasmonic lattice with chiral configuration that provides parallel angular momentum and spin components, one can trigger the strength of the SOC phenomena in photonic or plasmonic crystals. Our study gives insight into the design of novel plasmonic devices with polarization-dependent directionality of the Bloch plasmons. We expect spin-orbit interactions in plasmonics will find much more scientific interests and potential applications with the continuous development of nanofabrication methodologies and uncovering new aspects of spin-orbit interactions.
Article
Chemistry, Physical
Rui Zhao, Xingguang Liu, Junqing Li, Yingjie Zhang
Summary: This paper investigates the propagating behavior of surface plasmons in chiral media and proposes a new method for detecting the chirality of the environment. The features of SPPs in chiral environment are theoretically revealed, and the effects of medium chirality and graphene chemical potential on SPPs are explored. Additionally, this research provides new opportunities for the surface plasmonic wave theory on waveguides with multiple graphene sheets and the design of nanophotonic functional devices.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Yuqin Zhang, Jianshan An, Xingqi An, Xiangyu Zeng, Changwei He, Guiyuan Liu, Chuanfu Cheng, Hongsheng Song
Summary: The superposition of orbital angular momentum (OAM) in a surface plasmon polariton (SPP) field has attracted much attention in recent years. In this study, a plasmonic metasurface consisting of segmented spiral-shaped nanoslits is proposed to generate the superposition of two OAM states with arbitrary topological charges (TCs) and independently modulate their relative amplitudes. This design scheme offers opportunities for developing practical plasmonic devices and on-chip applications.
Article
Optics
Xiaodong Zhang, Depeng Kong, Yu Zhao, Ningtao Ma
Summary: In this paper, a plasmonic metasurface based on the geometric phase principle is designed and fabricated to generate scalar and vector vortex beams. The work provides a new idea for the development of a multivortex beam converter.
Article
Chemistry, Multidisciplinary
Fitri Oktafiani, Jun-Quan Chen, Po-Tsung Lee
Summary: Recent development in particle manipulation has increased the demand for dynamic optical tweezer structures. In this study, a plasmonic vortex lens (PVL) with multiple arms and a circular groove (CG) is proposed and demonstrated. Numerical simulations show that the PVL can efficiently rotate and trap microparticles by adjusting the polarization direction and groove radius. This research offers an efficient way to manipulate microparticles for various applications.
NANOSCALE ADVANCES
(2023)
Article
Physics, Applied
Atreyie Ghosh, Sena Yang, Yanan Dai, Zhikang Zhou, Tianyi Wang, Chen-Bin Huang, Hrvoje Petek
Summary: Topology is an intrinsic property of orbital symmetry and elemental spin-orbit interaction, and designed optical fields can break existing symmetries to impose topology. Through photonic spin-orbit interaction, light can induce topological interactions in matter, such as chiral chemistry, or non-Abelian physics.
APPLIED PHYSICS REVIEWS
(2021)
Article
Materials Science, Multidisciplinary
Joao Cunha, Alessandro Alabastri, Remo Proietti Zaccaria
Summary: In this study, finite element method simulations were used to investigate the nanofocusing effect of electromagnetic energy in plasmonic conical structures. It was found that in addition to the broadband nanofocusing, narrowband Fabry-Perot-like resonances were also observed, which could enhance the temperature localization and provide an extra degree of freedom for tuning the temperature localization.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Optics
Wenjie Yao, Francesc Verdugo, Henry O. Everit, Rasmus E. Christiansen, Steven G. Johnson
Summary: We propose a general framework for inverse design of nanopatterned surfaces that maximize surface-enhanced Raman spectra from randomly distributed molecules. Our optimized structures outperform coating with optimized spheres or bowtie structures by about 4 and 20 times, respectively, when considering nonlinear damage effects.
Article
Chemistry, Physical
Luis Cerdan, Alejandro Manjavacas
Summary: Metallic nanostructures with optical gain show enhanced optical responses and can be used to explore phenomena such as parity-time symmetry and nonreciprocity. However, the complexity of these systems often requires simplified gain models. In this study, we analyzed the optical response of a small active metallic nanoparticle using a semianalytical model that accounts for the nonlinear nature of the gain. We found that the optical response of the nanoparticle is greatly enhanced under weak probe fields, but becomes passive when the probe field strength depletes the excited-state population of the gain medium. Our results help to clarify the limits of linear models used to describe gain in plasmonic nanostructures, opening up new possibilities for applications.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Parmeet Dhindsa, David Solti, Christian R. Jacobson, Anvy Kuriakose, Gopal Narmada Naidu, Aaron Bayles, Yigao Yuan, Peter Nordlander, Naomi J. Halas
Summary: This study provides direct insight into the role of catalyst molecular structure in controlling the morphology of aluminum nanocrystals (Al NCs) by systematically modifying the catalyst molecular structure.
Article
Nanoscience & Nanotechnology
Lauren Zundel, Kellen Malone, Luis Cerdan, Rosario Martinez-Herrero, Alejandro Manjavacas
Summary: Thanks to their ability to support localized surface plasmons, metallic nanostructures have become ideal tools for converting light into heat at the nanoscale, leading to the field of thermoplasmonics. When arranged in a periodic array, metallic nanostructures can generate a stronger and more spectrally narrow optical response known as a lattice resonance. Through comprehensive analysis, it has been shown that arrays supporting a lattice resonance can absorb more energy and achieve a larger temperature increase under pulsed illumination conditions. This research paves the way for thermoplasmonics applications utilizing the exceptional optical response and tunability provided by lattice resonances.
Article
Chemistry, Multidisciplinary
Stephen A. Lee, Christopher T. Kuhs, Emily K. Searles, Henry O. Everitt, Christy F. Landes, Stephan Link
Summary: In this study, time-resolved emission upconversion microscopy was used to investigate the lifetime and energy-dependent cooling of d-band holes formed in gold nanoparticles by plasmon excitation and decay.
Article
Chemistry, Multidisciplinary
Mirko Vanzan, Gabriel Gil, Davide Castaldo, Peter Nordlander, Stefano Corni
Summary: Hot electron photocatalysis is a fascinating field with great technological potential. However, the mechanisms behind it are not fully understood. In this study, we propose a mechanism based on transient electron spillover and energy release into vibrational modes. Using real-time Time Dependent Density Functional Theory, we simulate the dynamics of hot electrons moving on chains of Ag or Au atoms with different adsorbates. Our results show that specific modes are selectively activated, and the energy transfer depends on the adsorbate, metal, and hot electron energy. This mechanism could play a significant role in hot electron photocatalysis.
Article
Physics, Multidisciplinary
Juan R. Deop-Ruano, Alejandro Manjavacas
Summary: Within the framework of fluctuational electrodynamics, this study investigates the simultaneous transfer of energy and angular momentum in a pair of rotating nanostructures. The results demonstrate that the radiative heat transfer between the nanostructures can be influenced by their rotation, leading to an increase, decrease, or even reversal of the transfer compared to non-rotating conditions. This work uncovers the counterintuitive phenomena resulting from the simultaneous transfer of energy and angular momentum in rotating nanostructures.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Masoumeh Izadparast, Gururaj V. Naik, Henry O. Everitt, Hamidreza Ramezani
Summary: Ring laser gyroscopes (RLGs) based on non-Hermitian exceptional points (EPs) have gained attention for their exceptional sensitivity. This study enhances the sensitivity of coupled dimers in RLGs by adding more dimers in an array. The lattice gyroscopes exhibit an enhanced effective coupling rate between the gain and loss resonators at the EP, leading to greater sensitivity to angular rotation rate. This work paves the way for EP-based RLGs with the necessary sensitivity for GPS-free navigation.
OPTICAL MATERIALS EXPRESS
(2023)
Article
Materials Science, Multidisciplinary
Yidong Chong, Henry O. Everitt, Vincenzo Galdi, Mercedeh Khajavikhan, Gururaj V. Naik
Summary: This article is an introduction to the feature issue of Optical Materials Express on Non-Hermitian Optics and Photonics.
OPTICAL MATERIALS EXPRESS
(2023)
Article
Nanoscience & Nanotechnology
Luis Cerdan, Lauren Zundel, Alejandro Manjavacas
Summary: Lattice resonances are collective electromagnetic modes supported by periodic arrays of metallic nanostructures. Recent studies have shown that arrays with chiral unit cells can exhibit lattice resonances with different responses to right- and left-handed circularly polarized light. In this study, we investigate lattice resonances supported by square bipartite arrays that function as 2.5-dimensional arrays. We find that despite the achirality of the unit cell, these systems can support lattice resonances with almost perfect chiral responses and very large quality factors.
Article
Engineering, Electrical & Electronic
Federica Granata, Noemi Pirillo, Alessandro Alabastri, Andrea Schirato, Luigi Bruno, Roberta Costa, Natalia Malara, Valentina Onesto, Maria Laura Coluccio, Mario Iodice, Giuseppe Coppola, Francesco Gentile
Summary: Soft plasmonic devices, made of materials such as polydimethylsiloxane (PDMS), are low weight, low cost, flexible, and exhibit improved mechanical properties. These devices have the potential to serve as efficient biosensors in various fields, due to their ability to enhance the local electromagnetic field and maintain the features of conventional nano-optic structures.
MICRO AND NANO ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Yilong Ju, Oara Neumann, Mary Bajomo, Yiping Zhao, Peter Nordlander, Naomi J. Halas, Ankit Patel
Summary: This article presents a machine learning algorithm that can identify chemicals by matching their SERS spectra to a standard Raman spectral library. The algorithm uses a facial recognition-like approach for spectral recognition and quantifies the degree of similarity to a Raman spectrum using a metric called Characteristic Peak Similarity (CaPSim). The analysis shows that CaPSim outperforms existing spectral matching algorithms in terms of accuracy. This machine learning-based approach could greatly facilitate the spectroscopic identification of molecules in fieldable SERS applications.
Article
Nanoscience & Nanotechnology
Alejandro Manjavacas, F. Javier Garcia de Abajo
Summary: Single-photon emitters are essential for quantum technologies, but generating single photons along specific directions usually requires complex configurations. In this study, we propose a photon source that can efficiently generate single photons along guided modes. By placing a quantum emitter in a periodically patterned linear waveguide, the emission of photons is preferentially directed along the waveguide in a region close to the period, resulting in a significant reduction in temporal uncertainty. Our research opens up a new approach for producing highly directional single photons with reduced temporal uncertainty.
Article
Chemistry, Multidisciplinary
Seung-Hoon Lee, Brandon Iglesias, Henry O. Everitt, Jie Liu
Summary: Hybrid gas/liquid-fed electrochemical flow reactors offer advantages in selectivity and production rates for CO2 conversion, but optimizing conditions for desired products remains a fundamental question. We investigated how hydrocarbon product selectivity depends on controllable parameters in the CO2 reduction reaction. Changing from dry to humidified CO2 dramatically altered product selectivity, indicating the influence of water vapor on reaction pathways and intermediates.