Article
Chemistry, Multidisciplinary
Wannes Peeters, Shuichi Toyouchi, Yasuhiko Fujita, Mathias Wolf, Beatrice Fortuni, Eduard Fron, Tomoko Inose, Johan Hofkens, Takahiko Endo, Yasumitsu Miyata, Hiroshi Uji-i
Summary: Tip-enhanced photoluminescence (TEPL) microscopy overcomes the diffraction-limited background signal by using remote excitation, achieving higher spatial resolution. Two probe designs were evaluated, and spatial heterogeneity was successfully demonstrated on a MoSe2/WSe2 lateral heterostructure.
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
Nanoscience & Nanotechnology
Bin Meng, Yong Xie, Le Chen, Haitao Wang, Ming Li, Zhuxin Dong
Summary: This paper presents a convenient technical scheme for enhancing the performance of atomic force microscopy (AFM) tips in tip-enhanced Raman spectroscopy (TERS) applications. The silver decoration on homemade tips is confined to the apex of commercial tips through an AFM-controlled electrochemical reaction. The efficiency of the metal coating is ensured by the reduction of Ag+ in a highly sealed environment. Key factors affecting the process include the use of silver nitrate solution, ambient relative humidity and temperature, electric potential bias, and tip-surface distance. The silver-coated tips are then tested for TERS measurement of carbon nanotubes (CNTs), resulting in simultaneous characterization of the CNTs' morphology and chemical properties. The Raman spectra show that our plasmonic tip exhibits a local field signal increase of approximately 30-fold, and the corresponding TERS image can resolve at the single-pixel level laterally.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Multidisciplinary Sciences
Ryo Kato, Toki Moriyama, Takayuki Umakoshi, Taka-aki Yano, Prabhat Verma
Summary: In this study, long-duration TERS imaging of a micrometer-sized WS2 sample was achieved in a reproducible manner, enabling the detection of nanoscale defects and rare optical signals in large area 2D materials.
Article
Chemistry, Physical
Chih-Feng Wang, Patrick Z. El-Khoury
Summary: The study reveals that nonlinear optical processes can be enhanced at plasmonic tip-sample nanojunctions, allowing for high-spatial-resolution chemical analysis through enhanced spectroscopies.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Yu E. Vysokikh, T. Mikhailova, S. Yu Krasnoborodko, A. S. Kolomiytsev, O. I. Ilin, A. N. Shaposhnikov, V. N. Berzhansky, M. F. Bulatov, D. Churikov, V. Shevyakov
Summary: The study discusses the importance of improving magnetic structure investigation with the lowest possible resolution for the study and practical implementation of fundamental magnetism. By using scanning near-field magneto-optical microscopy (SNMOM) and new technology based on focused ion beam (FIB) treatment to produce aperture cantilevers with carbon hollow pyramid tip (ACCT), it is shown that ACCT have better light transmission coefficients compared to commonly used aperture silicon cantilevers.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Chemistry, Physical
Brian T. O'Callahan, Patrick Z. El-Khoury
Summary: Tip-enhanced Raman spectroscopy is a powerful technique for high-resolution chemical imaging. It can track plasmon-induced/enhanced chemical reactions and provide accurate spectral assignments.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Shamsul Abedin, Khokan Roy, Xin Jin, Hui Xia, S. R. J. Brueck, Eric O. Potma
Summary: We discuss an experimental configuration of {Au film}-molecule-{Au particle} or {Au film}-molecule-{Si particle} nanojunction for wide-field surface-enhanced CARS (SE-CARS) measurements. We successfully generate detectable coherent Raman response from a molecular monolayer using the lowest reported average power densities. By using high-index dielectric particles on top of a thin metal film, we demonstrate repeatable SE-CARS measurements, paving the way for next-generation chemical and biomolecular sensing assays.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Denis E. Tranca, Stefan G. Stanciu, Radu Hristu, Adrian M. Ionescu, George A. Stanciu
Summary: We present a viable method to modify the refractive index of PMMA by focusing a femtosecond pulsed near-infrared laser beam on the apex of a metalized nanosized tip. The refractive index can be changed over a circular area with a diameter <200 nm under 790 nm illumination, representing a four-fold increase in resolution compared to the current state-of-the-art methods. This method can have important applications in the fabrication of photonic crystal lattices and surface waveguides.
APPLIED SURFACE SCIENCE
(2023)
Review
Chemistry, Multidisciplinary
Patrick Z. Z. El-Khoury
Summary: This article summarizes the lessons learned from ambient tip-enhanced Raman (TER) mapping of molecules interacting with plasmonic nanostructures. It demonstrates that various physical and chemical phenomena play a role in producing high-resolution TER spectral images. Consequently, selectively tracking interfacial chemical transformations via TERS is more challenging than currently recognized.
CHEMICAL COMMUNICATIONS
(2023)
Review
Chemistry, Multidisciplinary
Patrick Z. El-Khoury
Summary: The article discusses the historical focus of molecular spectroscopists on the right-hand side of the Schrödinger equation and introduces the less emphasized but equally exciting world of tip-enhanced Raman scattering (TERS) for characterizing molecule properties and local environments. TERS enables ultrahigh spatial resolution and ultimate sensitivity for single molecule detection and chemical fingerprinting, while also allowing for the study of spatially varying optical fields and plasmon-enhanced chemical transformations.
ACCOUNTS OF CHEMICAL RESEARCH
(2021)
Article
Chemistry, Multidisciplinary
Kathrin Kroth, Philip Klement, Limei Chen, Sangam Chatterjee, Peter J. Klar
Summary: Tip-induced optical spectroscopy can overcome the resolution limits of conventional optical techniques for studying sub-nm sized objects. However, there are restrictions for spatially extended samples due to perturbations caused by the tip. Additionally, the optical response is influenced by the type of tip and substrate used.
Article
Chemistry, Physical
Yujing Guo, Shuyi Zhu, Haoming Bao, Hao Fu, Hongwen Zhang, Le Zhou, Yue Li, Weiping Cai
Summary: This study demonstrates the significant impact of interfacial defects on the SERS activity and provides important guidance for the design and fabrication of efficient SERS substrates.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Review
Chemistry, Physical
Da Xu, Boqun Liang, Yaodong Xu, Ming Liu
Summary: Tip-enhanced Raman spectroscopy (TERS) imaging is a super-resolution technique that combines the advantages of surface-enhanced Raman spectroscopy (SERS) and scanning probe microscopy (SPM). It is an essential nanospectroscopic characterization technique for various fields. This review provides a comprehensive overview of the state-of-the-art TERS probe designs, including their working mechanisms, configurations, and performance. It also discusses emerging novel TERS probe designs and their critical aspects, as well as the latest TERS applications and future perspectives.
Article
Optics
Korbinian J. Kaltenecker, Shreesha D. S. Rao, Mattias Rasmussen, Henrik B. Lassen, Edmund J. R. Kelleher, Enno Krauss, Bert Hecht, N. Asger Mortensen, Lars Gruener-Nielsen, Christos Markos, Ole Bang, Nicolas Stenger, Peter Uhd Jepsen
Summary: This study developed a low-noise supercontinuum (SC) source for high resolution, spectrally resolved near-field measurements in the near-infrared (NIR) region. The SC light source was used to demonstrate the first NIR, spectrally resolved s-SNOM measurement and characterize the dispersion curve of surface plasmon polariton (SPP) waves in the NIR, representing a technological breakthrough for potential new applications in near-field studies.
Article
Chemistry, Physical
Cherrie May Olaya, Norihiko Hayazawa, Nathaniel Hermosa, Takuo Tanaka
Summary: In this study, surface plasmon resonance (SPR) was used to enhance the angular Goos-Hanchen (GH) shift. By focusing the incident beam to a small beam waist, a significant increase in the angular GH shift was induced, while the spatial GH shift was negligible. Despite decreased efficiency in surface plasmon excitation due to the focused geometry, a large enhancement in the angular GH shift was demonstrated.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Optics
Marilou Cadatal-Raduban, Masao Yoshino, Yuui Yokota, Akira Yoshikawa, Norihiko Hayazawa, Daizo Asano, Keito Shinohara, Toshihiko Shimizu, Nobuhiko Sarukura, Kohei Yamanoi
Summary: A scheme for imaging mid-infrared (MIR) wavelengths using pre-excitation-assisted up-conversion luminescence in lanthanide ion-doped Self-organizing Optical Fiber Array (SOFIA) crystal is proposed. The proposed scheme enables MIR wavelength detection and imaging using low-cost optics and silicon-based detectors in the visible spectral region, utilizing trivalent erbium, thulium, holmium, and neodymium for imaging MIR wavelengths.
Article
Chemistry, Multidisciplinary
Francesca Celine I. Catalan, Le The Anh, Junepyo Oh, Emiko Kazuma, Norihiko Hayazawa, Norihito Ikemiya, Naoki Kamoshida, Yoshitaka Tateyama, Yasuaki Einaga, Yousoo Kim
Summary: This study used low-temperature scanning tunneling microscopy to investigate the atomic-scale morphology and electronic structures of boron-doped diamond electrodes. It found that doped diamond surfaces exhibit graphitized domains affected by the dopants, with the graphitization uniquely observed in BDD (111). These observations provide insights into the role of dopants in modulating the conductivity of diamond and other functional doped materials.
ADVANCED MATERIALS
(2021)
Article
Chemistry, Physical
Misun Hong, Yasuyuki Yokota, Raymond A. Wong, Norihiko Hayazawa, Emiko Kazuma, Yousoo Kim
Summary: In this study, the application of UPD metals in catalyzing photoreactions of adsorbed molecules under the excitation of surface plasmons was demonstrated. The formation of DMAB was enhanced on the Ag surface deposited via UPD, indicating that the surface of UPD Ag played a catalytic role in the reduction of the nitro group. Overall, surface modification via UPD offers a potential strategy for controllably tuning the surface and interface chemistry.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Yasuyuki Yokota, Raymond A. Wong, Misun Hong, Norihiko Hayazawa, Yousoo Kim
Summary: Fluorescence and Raman scattering spectroscopies are widely used in chemistry, electrochemistry, and biochemistry for acquiring detailed molecular information at interfaces. A novel method using a monatomic layer of iodine as the dielectric layer has been proposed for simultaneous measurement of dye molecules on a metal surface, showing potential for various applications in catalytic chemistry and electrochemistry. This proposed multimodal strategy involves quenching the photoexcited state of molecules near the metal surface to weaken fluorescence intensity and using the resonance effect to enhance Raman signals.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Chi Zhang, Rafael B. Jaculbia, Yusuke Tanaka, Emiko Kazuma, Hiroshi Imada, Norihiko Hayazawa, Atsuya Muranaka, Masanobu Uchiyama, Yousoo Kim
Summary: The study demonstrates a methodology to visualize and identify the generated pi-skeletons at the single-chemical-bond level on the surface, enabling precise bond control. Electronic features and vibrational modes of the carbon skeletons are resolved in real space using a combination of STM/STS and TERS techniques, crucial for generating low-dimensional carbon nanostructures with atomic precision.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Analytical
Cherrie May Olaya, Norihiko Hayazawa, Maria Vanessa Balois-Oguchi, Nathaniel Hermosa, Takuo Tanaka
Summary: The study demonstrates potential molecular monolayer detection through measurements of surface plasmon resonance and angular Goos-Hanchen shift. The presence of a benzenethiol self-assembled monolayer on a gold substrate enhances the Goos-Hanchen shift, dominated by angular shift.
Article
Optics
Lean Dasallas, Rafael Jaculbia, Maria Vanessa Balois-Oguchi, Wilson Garcia, Norihiko Hayazawa
Summary: This study investigated the impact of the detection angle and substrate on the analysis of the polarization properties of 1D dipole emission. The analytical expression of dipole emission was modified using coordinate transformation. The effects of different substrates (free space, dielectric substrate, and metallic substrate) and detection angle on determining the dipole orientation were discussed. This work is significant for analyzing dipole emission signals, particularly in near-field optical spectroscopy based on scanning tunneling microscopy and atomic force microscopy.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2022)
Article
Physics, Condensed Matter
Maria Herminia M. Balgos, Mary Clare S. Escano, Rafael B. Jaculbia, Tien Quang Nguyen, Elizabeth Ann P. Prieto, Elmer S. Estacio, Arnel A. Salvador, Armando S. Somintac, Masahiko Tani, Norihiko Hayazawa, Yousoo Kim
Summary: By combining STM and spectroscopy with density functional theory calculations, the electronic properties of the subsurface arsenic antisite defect (As-Ga) in undoped gallium arsenide (GaAs) lattice were clearly delineated from those of surrounding As atoms. These results offer insights for surface/subsurface defect engineering at the atomic scale.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Atsushi Nakayama, Yasuaki Kumamoto, Masafumi Minoshima, Kazuya Kikuchi, Atsushi Taguchi, Katsumasa Fujita
Summary: This study demonstrates the use of photopolymerization without photoinitiators to fabricate 3D structures using biocompatible materials. The material properties of poly(ethylene glycol) diacrylate (PEGda) and collagen are preserved, making them suitable for applications with live cells.
ADVANCED OPTICAL MATERIALS
(2022)
Review
Chemistry, Physical
Yasuyuki Yokota, Misun Hong, Norihiko Hayazawa, Yousoo Kim
Summary: This review focuses on the electrochemical applications of tip-enhanced Raman spectroscopy (TERS). TERS combines the advantages of scanning probe microscopy (SPM) and Raman spectroscopy, allowing for high-resolution imaging of surface morphology and chemical information in an electrochemical environment. The review summarizes the pioneering work done on TERS systems in liquid and electrochemical environments, provides an overview of the typical instrumentation used in electrochemical TERS (EC-TERS) based on electrochemical scanning tunneling microscopy (EC-STM), and highlights the advancements in EC-TERS studies of events at interfaces, such as potential-dependent structural changes and electrochemical reactions. Current issues and future prospects of EC-TERS for microscopic studies of electrochemical interfaces are also discussed.
SURFACE SCIENCE REPORTS
(2022)
Article
Chemistry, Physical
Maria Vanessa Balois-Oguchi, Norihiko Hayazawa, Satoshi Yasuda, Katsuyoshi Ikeda, Nguyen Tien Quang, Mary Clare Escano, Takuo Tanaka
Summary: Wrinkles are inevitable during the growth of graphene, and they are influenced by the thermal expansion coefficients of graphene and the underlying substrate. The shape and strain variations of micrometer-sized wrinkles have been found to affect the electronic properties of graphene. This study investigates the physical and electronic nature of nanometer-sized wrinkles using tip-enhanced Raman spectroscopy (TERS), which is essential for the characterization of nanodevices.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Instruments & Instrumentation
M. H. Balgos, N. Hayazawa, M. Tani, T. Tanaka
Summary: We propose a fast pump modulation scheme in a terahertz time domain spectroscopy (THz-TDS) system by utilizing the megahertz repetition rate of the pump pulse for lock-in detection. This scheme enables rapid data acquisition times and detection of oscillating signals with frequencies up to 10 kHz. The use of an electro-optic modulator (EOM), operated as a pulse picker, allows for directly using the megahertz laser repetition rate as the reference modulation frequency.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2023)
Article
Chemistry, Physical
Yuika Saito, Takahiro Kondo, Sora Harada, Ryo Kitaura, Maria Vanessa Balois-Oguchi, Norihiko Hayazawa
Summary: In this study, we used polarization resonance Raman microscopy to investigate the interactions between single-walled carbon nanotubes (SWCNTs) and encapsulated molecules. We focused on C-70 encapsulated in SWCNTs and examined the Raman spectral pattern under different laser polarizations and excitation wavelengths. Our results showed that the resonance Raman process was modulated by a charge transfer contribution between C-70 and SWCNTs, which depended on the incident polarization and excitation wavelength. The intensity of the local electronic field inside a SWCNT was higher for parallel excitation than perpendicular excitation when the nanotubes were bundled.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Proceedings Paper
Engineering, Industrial
Atsushi Nakayama, Yasuaki Kumamoto, Atsushi Taguchi, Katsumasa Fujita
Summary: This study successfully fabricated three-dimensional micro/nano structures of biocompatible materials using two-photon fabrication technique without the need for photoinitiators. By utilizing a visible-wavelength femtosecond pulsed laser, two-photon polymerization was induced in deep UV absorbing moieties, and the photo-chemical process of the biocompatible material upon visible pulsed laser irradiation was investigated using Raman spectral change.
ADVANCED FABRICATION TECHNOLOGIES FOR MICRO/NANO OPTICS AND PHOTONICS XV
(2022)
