Article
Materials Science, Multidisciplinary
Mingze He, Lucas Lindsay, Thomas E. Beechem, Thomas Folland, Joseph Matson, Kenji Watanabe, Andrey Zavalin, Akira Ueda, Warren E. Collins, Takashi Taniguchi, Joshua D. Caldwell
Summary: Phonon polaritons (PhPs) have potential applications but are limited by the spectral gap between cubic and hexagonal BN allotropes. Isotopically engineering hBN and cBN can improve optic phonon lifetimes and frequencies, with hBN showing enhancements and cBN showing reductions in lifetimes with isotopic enrichment. Reducing extrinsic defects in isotopically engineered cBN could help overcome restrictions in the molecular-fingerprint region.
JOURNAL OF MATERIALS RESEARCH
(2021)
Article
Nanoscience & Nanotechnology
Andrea Mancini, Lin Nan, Fedja J. Wendisch, Rodrigo Berte, Haoran Ren, Emiliano Cortes, Stefan A. Maier
Summary: In this work, the dispersion of SPhPs in silicon carbide free-standing membranes was obtained through near-field spectroscopy. Multiple branches were observed, which supports the use of free-standing membranes as a platform for phonon polaritonics.
Article
Optics
Penghua Ma, Kaizhen Liu, Guangyan Huang, Youyi Ding, Wei Du, Tao Wang
Summary: This study demonstrates vibrational strong coupling (VSC) between organic molecular vibrations and mid-infrared plasmons on metallic antennas using quartz as an epsilon-near-zero (ENZ) substrate. The coupling strength is proportional to the square root of the PMMA layer thickness and is influenced by the polarization of the incident light. These findings present a new possibility for achieving VSC with metallic antennas and pave the way for enhancing the sensitivity of molecular vibrational spectroscopy.
Article
Multidisciplinary Sciences
Irene Dolado, Carlos Maciel-Escudero, Elizaveta Nikulina, Evgenii Modin, Francesco Calavalle, Shu Chen, Andrei Bylinkin, Francisco Javier Alfaro-Mozaz, Jiahan Li, James H. Edgar, Felix Casanova, Saul Velez, Luis E. Hueso, Ruben Esteban, Javier Aizpurua, Rainer Hillenbrand
Summary: In this study, nanoscale mapping of vibrational strong coupling between organic molecules and nanoresonators is achieved by remote near-field spectroscopy. The results demonstrate the localized hybrid polariton modes and coupling strengths on a single nanoresonator level, providing insights into the nanoscale vibrational strong coupling phenomenon.
NATURE COMMUNICATIONS
(2022)
Article
Optics
Daehan Yoo, Fernando de Leon-Perez, Matthew Pelton, In-Ho Lee, Daniel A. Mohr, Markus B. Raschke, Joshua D. Caldwell, Luis Martin-Moreno, Sang-Hyun Oh
Summary: Research demonstrates that ultrastrong coupling between phonons and gap plasmons in nanocavities can lead to a modal splitting of up to 50% of the resonant frequency, opening up new possibilities for ultrastrong coupling applications.
Article
Multidisciplinary Sciences
Sergey G. Menabde, Sergejs Boroviks, Jongtae Ahn, Jacob T. Heiden, Kenji Watanabe, Takashi Taniguchi, Tony Low, Do Kyung Hwang, N. Asger Mortensen, Min Seok Jang
Summary: This research uses large-area monocrystalline gold flakes as a low-loss substrate for image polaritons, accurately measures the complex propagation constant of polaritons in van der Waals crystals, and finds that the propagation loss and normalized propagation length of image phonon-polaritons have specific spectral dependencies.
Article
Chemistry, Multidisciplinary
Patricia Aguilar-Merino, Gonzalo Alvarez-Perez, Javier Taboada-Gutierrez, Jiahua Duan, Ivan Prieto, Luis Manuel Alvarez-Prado, Alexey Y. Nikitin, Javier Martin-Sanchez, Pablo Alonso-Gonzalez
Summary: Layered materials bonded by weak van der Waals forces have attracted significant attention in nano-optics due to their ability to support phonon polaritons with strong electromagnetic confinement. Using near-field microscopy, researchers were able to accurately extract the permittivity of alpha-MoO3 and sense its local dielectric environment, silica, demonstrating the versatility of phonon polaritons nanoimaging for characterizing local optical properties of dielectric substrates.
Article
Chemistry, Multidisciplinary
Qing Zhang, Qingdong Ou, Guangwei Hu, Jingying Liu, Zhigao Dai, Michael S. Fuhrer, Qiaoliang Bao, Cheng-Wei Qiu
Summary: In this study, the issues of limited photon confinement, in-plane hyperbolicity, and unidirectional propagation of bulk SPhPs were collectively addressed by constructing a heterostructural interface between biaxial van der Waals material and bulk polar dielectric. The hybridized SPhPs showed in-plane hyperbolicity with a large confinement factor (>100), and steerable and unidirectional polariton excitation was achieved. This approach provides a generalizable framework for manipulating nanolight flow in hybrid systems consisting of anisotropic materials and polar dielectrics.
Article
Chemistry, Physical
Xiaoze Liu, Jun Yi, Sui Yang, Erh-Chen Lin, Yue-Jiao Zhang, Peiyao Zhang, Jian-Feng Li, Yuan Wang, Yi-Hsien Lee, Zhong-Qun Tian, Xiang Zhang
Summary: Nonlinear phonon scattering in monolayer MoS2 strongly coupled to a plasmonic cavity mode has been demonstrated, showing enhanced valley polarization and sustained coherence in the stimulated regime. This suggests the potential of valley-cavity-based systems for various applications in cavity quantum electrodynamics.
Article
Materials Science, Multidisciplinary
Bo Qiang, Alexander M. Dubrovkin, Harish N. S. Krishnamoorthy, Qian Wang, Nikolay Zheludev, Qi Jie Wang
Summary: A phononic-dielectric metamaterial consisting of a 2D periodic array of germanium discs on silicon carbide was demonstrated, showing sharp resonances at a wavelength ten times larger than the lattice parameter. A blueshift in the resonant frequency was observed with an increase in disk size, attributed to the anomalous dispersion of surface polaritons. The researchers argue that this surface phonon-polariton metamaterial is a promising platform for applications requiring enhanced homogeneity of optical response, such as imaging, holography, and cloaking.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
A. Koudinov, E. Borisov, A. A. Shimko, Yu E. Kitaev, C. Trallero-Giner, T. Wojtowicz, G. Karczewski, S. Goupalov
Summary: An unusual fine spectrum of very narrow lines is observed in resonance Raman scattering from a CdTe quantum well. The visibility of this fine spectrum is improved by sample doping. The appearance of the four sideway lines of the fine spectrum is explained by the Raman scattering on the combination of LO and LA (or TA) phonons with excitons serving as intermediate states. The central line is due to elastic scattering and emission of a LO phonon.
Article
Materials Science, Multidisciplinary
Te-Huan Liu, Jiawei Zhou, Qian Xu, Xin Qian, Bai Song, Ronggui Yang
Summary: The study shows that long-range electron-phonon interaction can significantly suppress thermal conductivity in certain polar semiconductors by scattering acoustic phonons. The breaking of centrosymmetry has different effects on phonon transport in different crystal structures.
MATERIALS TODAY PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Krishna Chand Maurya, Dheemahi Rao, Shashidhara Acharya, Pavithra Rao, Ashalatha Indiradevi Kamalasanan Pillai, Shankar Kumar Selvaraja, Magnus Garbrecht, Bivas Saha
Summary: The interaction between light and collective charge oscillations and polar lattice vibrations plays a crucial role in confining light at deep subwavelength dimensions. This study demonstrates tunable short-wavelength infrared plasmon-polariton and long-wavelength infrared phonon-polariton in III-V group polar semiconducting scandium nitride thin films.
Article
Physics, Applied
Zhu Yuan, Yunji Meng, Weiliang Ma, Runkun Chen, Tao Wang, Peining Li
Summary: This study demonstrates theoretically and experimentally that the complex-valued wavevectors of hyperbolic phonon polaritons (HPhPs) can be accurately quantified by fitting the concave wavefront profiles. The experimental setup includes using a scanning near-field optical microscope to image the concave wavefronts of HPhPs.
APPLIED PHYSICS LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Rebecca Buechner, Thomas Weber, Lucca Kuhner, Stefan A. Maier, Andreas Tittl
Summary: This study demonstrates the ability to choose between weak and strong tip-antenna coupling regimes when using metallic tips in s-SNOM by carefully adjusting the illumination conditions and resonator orientation. It shows that highly scattering metallic tips can be used to map plasmonic modes with comparatively higher signal strengths. Additionally, the research reveals the collective effects of nanoantenna arrays and provides guidelines for optimized array designs for both near-field and far-field applications.
Article
Polymer Science
Matteo Sanviti, Lars Mester, Rainer Hillenbrand, Angel Alegria, DanielE. Martinez-Tong
Summary: In this study, nanostructured conducting PEDOT:PSS thin films were prepared using solvent vapor annealing (SVA) with tetrahydrofuran (THF) as the low boiling point solvent. Atomic Force Microscopy (AFM) was used to observe the development of distinct nanostructures with solvent exposure time. The physical properties of the nanostructures were evaluated through nanomechanical, nanoelectrical, and nanoinfrared (nano-FTIR) measurements. It was demonstrated that exposure to THF can effectively and selectively modify the surface nanostructure of PEDOT:PSS and thus its final properties. The nanoscale studies also provided evidence of molecular rearrangements during nanostructure fabrication, which is crucial for expanding the potential applications of this polymer in thermoelectric and optoelectronic devices.
Article
Multidisciplinary Sciences
Shu Chen, Andrei Bylinkin, Zhengtianye Wang, Martin Schnell, Greeshma Chandan, Peining Li, Alexey Y. Nikitin, Stephanie Law, Rainer Hillenbrand
Summary: This study successfully captures and analyzes the properties and dispersion of plasmon polaritons in thin Bi2Se3 layers using THz near-field imaging technique. The results show that the momentum and decay time of polaritons significantly increase compared to photons, but the propagation length is short. The study further reveals the coupling process between THz radiation and Dirac and Massive carriers on the surface of topological insulators and carriers and photons in the bulk.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Gonzalo Alvarez-Perez, Jiahua Duan, Javier Taboada-Gutierrez, Qingdong Ou, Elizaveta Nikulina, Song Liu, James H. Edgar, Qiaoliang Bao, Vincenzo Giannini, Rainer Hillenbrand, Javier Martin-Sanchez, Alexey Yu Nikitin, Pablo Alonso-Gonzalez
Summary: This article introduces a negative reflection optical phenomenon and directly visualizes polaritons at the nano scale. The research findings show that negative reflection can tune the wavelength and direction of polaritons, providing a new approach for realizing nanophotonics in low-loss natural media.
Article
Multidisciplinary Sciences
Qing Zhang, Qingdong Ou, Guangyuan Si, Guangwei Hu, Shaohua Dong, Yang Chen, Jincheng Ni, Chen Zhao, Michael S. Fuhrer, Yuanjie Yang, Andrea Alu, Rainer Hillenbrand, Cheng-Wei Qiu
Summary: Recent research has shown that highly asymmetric and unidirectional phonon polaritons can be excited by directly patterning high-symmetry crystal structures. Structural engineering in high-symmetry vdW materials allows versatile and robust control over the propagation of phonon polaritons, opening up new possibilities for controlling infrared polaritons.
Article
Chemistry, Multidisciplinary
Jose M. Pereira, Daniel Tezze, Iris Niehues, Yaiza Asensio, Haozhe Yang, Lars Mester, Shu Chen, Felix Casanova, Alexander M. Bittner, Maider Ormaza, Frederik Schiller, Beatriz Martin-Garcia, Rainer Hillenbrand, Luis E. Hueso, Marco Gobbi
Summary: The emergence of superconductivity and a charge density wave phase in air-stable organic cation intercalated MoS2 crystals is reported. The properties of the correlated electronic phases are shown to depend dramatically on the intercalated cation, demonstrating the potential of organic ion intercalation to finely tune the properties of 2D materials. Organic-ion intercalated MoS2 is established as a platform to study the emergence and modulation of correlated electronic phases.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Multidisciplinary Sciences
Irene Dolado, Carlos Maciel-Escudero, Elizaveta Nikulina, Evgenii Modin, Francesco Calavalle, Shu Chen, Andrei Bylinkin, Francisco Javier Alfaro-Mozaz, Jiahan Li, James H. Edgar, Felix Casanova, Saul Velez, Luis E. Hueso, Ruben Esteban, Javier Aizpurua, Rainer Hillenbrand
Summary: In this study, nanoscale mapping of vibrational strong coupling between organic molecules and nanoresonators is achieved by remote near-field spectroscopy. The results demonstrate the localized hybrid polariton modes and coupling strengths on a single nanoresonator level, providing insights into the nanoscale vibrational strong coupling phenomenon.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Alexey Y. Nikitin, Rainer Hillenbrand, Andrei Bylinkin, Francesco Calavalle, Maria Barra-Burillo, Roman V. Kirtaev, Elizaveta Nikulina, Evgeny Modin, Eli Janzen, James H. Edgar, Felix Casanova, Luis E. Hueso, Valentyn S. Volkov, Paolo Vavassori, Igor Aharonovich, Pablo Alonso-Gonzalez
Summary: Strong coupling between light and matter excitations in both mid-IR and visible frequency bands is achieved by introducing polaritonic nanoresonators, which can manipulate material properties and have potential applications in optoelectronics, nanophotonics, and quantum information.
Article
Chemistry, Physical
S. Chen, P. L. Leng, A. Konecna, E. Modin, M. Gutierrez-Amigo, E. Vicentini, B. Martin-Garcia, M. Barra-Burillo, I. Niehues, C. Maciel Escudero, X. Y. Xie, L. E. Hueso, E. Artacho, J. Aizpurua, I. Errea, M. G. Vergniory, A. Chuvilin, F. X. Xiu, R. Hillenbrand
Summary: By employing terahertz nanoscopy, it has been possible to image highly confined, in-plane anisotropic acoustic terahertz plasmon polaritons in monoclinic Ag2Te platelets placed above a Au layer, verifying a linear dispersion and elliptical isofrequency contour in momentum space.
Article
Optics
Edoardo Vicentini, Wiwat Nuansing, Iris Niehues, Iban Amenabar, Alexander Bittner, Rainer Hillernbrand, Martin Schnell
Summary: We have developed a detection technique for scattering-type scanning near-field optical microscopy (s-SNOM) that enables simultaneous near-field amplitude and phase imaging at different wavelengths. This technique, called multispectral pseudoheterodyne (PSH) interferometry, combines infrared lasers to form a beam with multiple laser lines and utilizes a time-multiplexing scheme with a single infrared detector. We have demonstrated the implementation of multispectral PSH in a commercial s-SNOM instrument and its application in real-time correction of negative phase contrast (NPC) for reliable imaging of weak IR absorption at the nanoscale. This technique shows potential in improving data throughput, reducing sample and interferometer drift, and establishing multicolor s-SNOM imaging as a regular imaging modality.
Article
Nanoscience & Nanotechnology
Eric Sidney Aaron Goerlitzer, Mario Zapata-Herrera, Ekaterina Ponomareva, Deborah Feller, Aitzol Garcia-Etxarri, Matthias Karg, Javier Aizpurua, Nicolas Vogel
Summary: Molecular chirality is transferred to plasmonic lattice modes, providing a effective and tunable means to control chirality. Non-close packed, periodic arrays of achiral gold nanoparticles embedded in a polymer film are used to demonstrate this chirality transfer. The surface lattice resonances become optically active in the presence of chiral molecules, showing handedness-dependent excitation. Numerical simulations and a semi-analytical model rationalize this chirality transfer.
Article
Nanoscience & Nanotechnology
Jorge Olmos-Trigo, Cristina Sanz-Fernandez, Diego R. Abujetas, Aitzol Garcia-Etxarri, Antonio Garcia-Martin
Summary: Spin-orbit interactions of light play a crucial role in various nanophotonic applications, but the study reveals that optical mirages can still appear when particles are illuminated by spinless beams. The research demonstrates that the interference between electric and magnetic dipoles, rather than the spin-orbit interactions, is responsible for the tilted position of the nanosphere.
Article
Spectroscopy
Alberto Villar, Santos Merino, Roberto A. Boto, Javier Aizpurua, Aitzol Garcia, Mikel Azkune, Joseba Zubia
Summary: The control of wine production requires extensive chemical analysis, with a focus on quantifying total and free SO2. Existing methods lack reproducibility and require sample treatment for SO2 extraction. This study proposes a new method using Surface-Enhanced Raman Spectroscopy (SERS) and Density Functional Theory (DFT) calculations to identify key molecules' vibrational modes contributing to free SO2 concentration. The combination of theoretical predictions and experimental outcomes allows for real-time monitoring, potentially enabling portable SERS detection for in-field measurements.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2023)
Article
Physics, Multidisciplinary
Jon Lasa-Alonso, Jorge Olmos-Trigo, Chiara Devescovi, Pilar Hernandez, Aitzol Garcia-Etxarri, Gabriel Molina-Terriza
Summary: We prove the nonexistence of passive antidual scatterers while providing a general proof in linear electromagnetic scattering theory. However, we find that scatterers satisfying the refractive index matching condition efficiently flip the helicity of the incident field without violating the law of energy conservation. Additionally, we discover that this condition is associated with the impedance matching condition in various electromagnetism contexts, especially in Fresnel's and Mie's scattering problems. Finally, we demonstrate that index-matched media induce resonant helicity mixing on propagating electromagnetic waves by linking the refractive index matching condition to the phenomenon of avoided crossing.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Optics
Iris Niehues, Lars Mester, Edoardo Vicentini, Daniel Wigger, Martin Schnell, Rainer Hillenbrand
Summary: Scattering-type scanning near-field optical microscopy (s-SNOM) enables nanoscale optical mapping of various material properties through interferometric recording of light scattered at a scanning probe tip. It reveals the local reflectivity and absorption of dielectric samples, such as biological materials or polymers, through near-field amplitude and phase signals of the scattered field. However, in certain conditions with weakly or non-absorbing material on a highly reflective substrate, a slight negative phase contrast can hinder the identification of weak infrared absorption materials. This effect is documented, and simple correction methods are demonstrated to remove the negative phase contrast and enable the identification of weak absorption contrasts.
