1
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Traeger GA, Teichmann MH, Schröder B, Wenderoth M. Combining grating-coupled illumination and image recognition for stable and localized optical scanning tunneling microscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:023702. [PMID: 36859060 DOI: 10.1063/5.0123604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 01/07/2023] [Indexed: 06/18/2023]
Abstract
Combining scanning tunneling microscopy (STM) and optical excitation has been a major objective in STM for the last 30 years to study light-matter interactions on the atomic scale. The combination with modern pulsed laser systems even made it possible to achieve a temporal resolution down to the femtosecond regime. A promising approach toward a truly localized optical excitation is featured by nanofocusing via an optical antenna spatially separated from the tunnel junction. Until now, these experiments have been limited by thermal instabilities introduced by the laser. This paper presents a versatile solution to this problem by actively coupling the laser and STM, bypassing the vibration-isolation without compromising it. We utilize optical image recognition to monitor the position of the tunneling junction and compensate for any movement of the microscope relative to the laser setup with up to 10 Hz by adjusting the beamline. Our setup stabilizes the focus position with high precision (<1 μm) on long timescales (>1 h) and allows for high resolution STM under intense optical excitation with femtosecond pulses.
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Affiliation(s)
- Georg A Traeger
- IV. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Lower Saxony, Germany
| | - Marlo H Teichmann
- IV. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Lower Saxony, Germany
| | - Benjamin Schröder
- IV. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Lower Saxony, Germany
| | - Martin Wenderoth
- IV. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Lower Saxony, Germany
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2
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Kozhina E, Bedin S, Martynov A, Andreev S, Piryazev A, Grigoriev Y, Gorbunova Y, Naumov A. Ultrasensitive Optical Fingerprinting of Biorelevant Molecules by Means of SERS-Mapping on Nanostructured Metasurfaces. BIOSENSORS 2022; 13:46. [PMID: 36671881 PMCID: PMC9855407 DOI: 10.3390/bios13010046] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/20/2022] [Accepted: 12/24/2022] [Indexed: 06/17/2023]
Abstract
The most relevant technique for portable (on-chip) sensors is Surface Enhanced Raman Scattering (SERS). This strategy crashes in the case of large (biorelevant) molecules and nano-objects, whose SERS spectra are irreproducible for "homeopathic" concentrations. We suggested solving this problem by SERS-mapping. We analyzed the distributions of SERS parameters for relatively "small" (malachite green (MG)) and "large" (phthalocyanine, H2Pc*) molecules. While fluctuations of spectra for "small" MG were negligible, noticeable distribution of spectra was observed for "large" H2Pc*. We show that the latter is due to a random arrangement of molecules with respect to "hot spot" areas, which have limited sizes, thus amplifying the lines corresponding to vibrations of different molecule parts. We have developed a method for engineering low-cost SERS substrates optimized for the best enhancement efficiency and a measurement protocol to obtain a reliable Raman spectrum, even for a countable number of large molecules randomly distributed over the substrate.
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Affiliation(s)
- Elizaveta Kozhina
- Laboratory of Plasmonics, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, bld. 1, 121205 Moscow, Russia
- Department of Advanced Photonics and Sensorics, Lebedev Physical Institute RAS, Troitsk Branch, Fizicheskaya Str. 11, 108840 Moscow, Troitsk, Russia
| | - Sergey Bedin
- Department of Advanced Photonics and Sensorics, Lebedev Physical Institute RAS, Troitsk Branch, Fizicheskaya Str. 11, 108840 Moscow, Troitsk, Russia
- Laboratory of Physics of Advanced Materials and Nanostructures, Moscow State Pedagogical University, Malaya Pirogovskaya St. 1-1, 119991 Moscow, Russia
- Laboratory for the Growth of Thin Films and Inorganic Nanostructures Center of Crystallography and Photonics of RAS, Leninskiy Prosp. 59, 119333 Moscow, Russia
| | - Alexander Martynov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskiy Prosp., 31 Building 4, 119071 Moscow, Russia
| | - Stepan Andreev
- Laboratory of Physics of Advanced Materials and Nanostructures, Moscow State Pedagogical University, Malaya Pirogovskaya St. 1-1, 119991 Moscow, Russia
| | - Alexey Piryazev
- Department of Chemistry, Moscow State University, Leninskie Gory, 1, 119991 Moscow, Russia
- Research Center of Genetics and Life Sciences, Research Direction–Biomaterials, Sirius University of Science and Technology, 1 Olympic Ave, 354340 Sochi, Russia
| | - Yuri Grigoriev
- Laboratory for the Growth of Thin Films and Inorganic Nanostructures Center of Crystallography and Photonics of RAS, Leninskiy Prosp. 59, 119333 Moscow, Russia
| | - Yulia Gorbunova
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskiy Prosp., 31 Building 4, 119071 Moscow, Russia
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskiy Prosp., 31, 119991 Moscow, Russia
| | - Andrey Naumov
- Department of Advanced Photonics and Sensorics, Lebedev Physical Institute RAS, Troitsk Branch, Fizicheskaya Str. 11, 108840 Moscow, Troitsk, Russia
- Laboratory of Physics of Advanced Materials and Nanostructures, Moscow State Pedagogical University, Malaya Pirogovskaya St. 1-1, 119991 Moscow, Russia
- Laboratory for Spectroscopy of Electronic Spectra of Molecules, Institute for Spectroscopy RAS, Fizicheskaya Str. 5, 108840 Moscow, Troitsk, Russia
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3
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Gu K, Sun M, Zhang Y. Tip-Enhanced Raman Spectroscopy Based on Spiral Plasmonic Lens Excitation. SENSORS (BASEL, SWITZERLAND) 2022; 22:5636. [PMID: 35957194 PMCID: PMC9371167 DOI: 10.3390/s22155636] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/22/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
In this study, we proposed the idea of replacing the traditional objective lens in bottom-illumination mode with a plasmonic lens (PL) to achieve tip-enhanced Raman spectroscopy (TERS). The electric field energy of surface plasmon polaritons (SPPs) of the spiral PL was found to be more concentrated at the focal point without any sidelobe using the finite-difference time domain (FDTD) method compared with that of a symmetry-breaking PL. This property reduces far-field background noise and increases the excitation efficiency of the near-field Raman signal. The disadvantage of only the near-field Raman scattering of samples at the center of the structure being detected when using an ordinary PL in TERS is overcome by using our proposed method of changing only the polarization of the incident light.
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4
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Fan Y, Jin D, Wu X, Fang H, Yuan X. Facilitating Hotspot Alignment in Tip-Enhanced Raman Spectroscopy via the Silver Photoluminescence of the Probe. SENSORS 2020; 20:s20226687. [PMID: 33238402 PMCID: PMC7700460 DOI: 10.3390/s20226687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 11/02/2020] [Accepted: 11/17/2020] [Indexed: 11/23/2022]
Abstract
A tip-enhanced Raman spectroscopy (TERS) system based on an atomic force microscope (AFM) and radially polarized laser beam was developed. A TERS probe with plasmon resonance wavelength matching the excitation wavelength was prepared with the help of dark-field micrographs. The intrinsic photoluminescence (PL) from the silver (Ag)-coated TERS probe induced by localized surface plasmon resonance contains information about the near-field enhanced electromagnetic field intensity of the probe. Therefore, we used the intensity change of Ag PL to evaluate the stability of the Ag-coated probe during TERS experiments. Tracking the Ag PL of the TERS probe was helpful to detect probe damage and hotspot alignment. Our setup was successfully used for the TERS imaging of single-walled carbon nanotubes, which demonstrated that the Ag PL of the TERS probe is a good criterion to assist in the hotspot alignment procedure required for TERS experiments. This method lowers the risk of contamination and damage of the precious TERS probe, making it worthwhile for wide adoption in TERS experiments.
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5
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Tabatabaei M, Caetano FA, Pashee F, Ferguson SSG, Lagugné-Labarthet F. Tip-enhanced Raman spectroscopy of amyloid β at neuronal spines. Analyst 2018; 142:4415-4421. [PMID: 29090690 DOI: 10.1039/c7an00744b] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The early stages of Alzheimer's disease pathogenesis are thought to occur at the synapse level, since synapse loss can be directly correlated with memory dysfunction. Considerable evidence has suggested that amyloid beta (Aβ), a secreted proteolytic derivative of amyloid precursor protein, appears to be a critical factor in the early 'synaptic failure' that is observed in Alzheimer's disease pathogenesis. The identification of Aβ at neuronal spines with high spatial resolution and high surface specificity would facilitate unraveling the intricate effect of Aβ on synapse loss and its effect on neighboring neuronal connections. Here, tip-enhanced Raman spectroscopy was used to map the presence of Aβ aggregations in the vicinity of the spines exposed to Aβ preformed in vitro. Exposure to Aβ was of 1 and 6 hours. The intensity variation of selected vibrational modes of Aβ was mapped by TERS for different exposure times to Aβ. Of interest, we discuss the distinct contributions of the amide modes from Aβ that are enhanced by the TERS process and in particular the suppression of the amide I mode in the context of recently reported observations in the literature.
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Affiliation(s)
- Mohammadali Tabatabaei
- Department of Chemistry and Centre for Advanced Materials and Biomaterials, University of Western Ontario, London, ON, Canada N6A 5B7.
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6
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Hermann RJ, Gordon MJ. Nanoscale Optical Microscopy and Spectroscopy Using Near-Field Probes. Annu Rev Chem Biomol Eng 2018; 9:365-387. [DOI: 10.1146/annurev-chembioeng-060817-084150] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Light-matter interactions can provide a wealth of detailed information about the structural, electronic, optical, and chemical properties of materials through various excitation and scattering processes that occur over different length, energy, and timescales. Unfortunately, the wavelike nature of light limits the achievable spatial resolution for interrogation and imaging of materials to roughly λ/2 because of diffraction. Scanning near-field optical microscopy (SNOM) breaks this diffraction limit by coupling light to nanostructures that are specifically designed to manipulate, enhance, and/or extract optical signals from very small regions of space. Progress in the SNOM field over the past 30 years has led to the development of many methods to optically characterize materials at lateral spatial resolutions well below 100 nm. We review these exciting developments and demonstrate how SNOM is truly extending optical imaging and spectroscopy to the nanoscale.
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Affiliation(s)
- Richard J. Hermann
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, USA;,
| | - Michael J. Gordon
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, USA;,
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7
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Optical fiber tips for biological applications: From light confinement, biosensing to bioparticles manipulation. Biochim Biophys Acta Gen Subj 2018; 1862:1209-1246. [DOI: 10.1016/j.bbagen.2018.02.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/26/2018] [Accepted: 02/13/2018] [Indexed: 12/15/2022]
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8
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Gao L, Zhao H, Li T, Huo P, Chen D, Liu B. Atomic Force Microscopy Based Tip-Enhanced Raman Spectroscopy in Biology. Int J Mol Sci 2018; 19:E1193. [PMID: 29652860 PMCID: PMC5979470 DOI: 10.3390/ijms19041193] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 04/09/2018] [Accepted: 04/10/2018] [Indexed: 12/15/2022] Open
Abstract
Most biological phenomena occur at the nanometer scale, which is not accessible by the conventional optical techniques because of the optical diffraction limitation. Tip-enhanced Raman spectroscopy (TERS), one of the burgeoning probing techniques, not only can provide the topography characterization with high resolution, but also can deliver the chemical or molecular information of a sample beyond the optical diffraction limitation. Therefore, it has been widely used in various structural analyses pertaining to materials science, tissue engineering, biological processes and so on. Based on the different feedback mechanisms, TERS can be classified into three types: atomic force microscopy based TERS system (AFM-TERS), scanning tunneling microscopy based TERS system (STM-TERS) and shear force microscopy based TERS system (SFM-TERS). Among them, AFM-TERS is the most widely adopted feedback system by live biosamples because it can work in liquid and this allows the investigation of biological molecules under native conditions. In this review, we mainly focus on the applications of AFM-TERS in three biological systems: nucleic acids, proteins and pathogens. From the TERS characterization to the data analysis, this review demonstrates that AFM-TERS has great potential applications to visually characterizing the biomolecular structure and crucially detecting more nano-chemical information of biological systems.
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Affiliation(s)
- Lizhen Gao
- Institute of Photo-biophysics, School of Physics and Electronics, Henan University, Kaifeng 475004, China.
| | - Huiling Zhao
- Institute of Photo-biophysics, School of Physics and Electronics, Henan University, Kaifeng 475004, China.
| | - Tianfeng Li
- Institute of Photo-biophysics, School of Physics and Electronics, Henan University, Kaifeng 475004, China.
| | - Peipei Huo
- Laboratory of Functional Molecules and Materials, School of Physics and Optoelectronic Engineering, Shandong University of Technology, Xincun West Road 266, Zibo 255000, China.
| | - Dong Chen
- Institute of Photo-biophysics, School of Physics and Electronics, Henan University, Kaifeng 475004, China.
| | - Bo Liu
- Institute of Photo-biophysics, School of Physics and Electronics, Henan University, Kaifeng 475004, China.
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9
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Milekhin AG, Rahaman M, Rodyakina EE, Latyshev AV, Dzhagan VM, Zahn DRT. Giant gap-plasmon tip-enhanced Raman scattering of MoS 2 monolayers on Au nanocluster arrays. NANOSCALE 2018; 10:2755-2763. [PMID: 29308796 DOI: 10.1039/c7nr06640f] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In this article, we present the results of a gap-plasmon tip-enhanced Raman scattering study of MoS2 monolayers deposited on a periodic array of Au nanostructures on a silicon substrate forming a two dimensional (2D) crystal/plasmonic heterostructure. We observe a giant Raman enhancement of the phonon modes in the MoS2 monolayer located in the plasmonic gap between the Au tip apex and Au nanoclusters. Tip-enhanced Raman mapping allows us to determine the gap-plasmon field distribution responsible for the formation of hot spots. These hot spots provide an unprecedented giant Raman enhancement of 5.6 × 108 and a spatial resolution as small as 2.3 nm under ambient conditions. Moreover, due to strong hot electron doping in the order of 1.8 × 1013 cm-2, we observe a structural change of MoS2 from the 2H to the 1T phase. Owing to the very good spatial resolution, we are able to spatially resolve those doping sites. To the best of our knowledge, this is the first time reporting of such a phenomenon with nm spatial resolution. Our results will open the perspectives of optical diagnostics with nanometer resolution for many other 2D materials.
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Affiliation(s)
- Alexander G Milekhin
- Rzhanov Institute of Semiconductor Physics RAS, Lavrentiev Ave. 13, 630090, Novosibirsk, Russia.
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10
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Poliani E, Wagner MR, Vierck A, Herziger F, Nenstiel C, Gannott F, Schweiger M, Fritze S, Dadgar A, Zaumseil J, Krost A, Hoffmann A, Maultzsch J. Breakdown of Far-Field Raman Selection Rules by Light-Plasmon Coupling Demonstrated by Tip-Enhanced Raman Scattering. J Phys Chem Lett 2017; 8:5462-5471. [PMID: 29064705 DOI: 10.1021/acs.jpclett.7b02505] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present an experimental study on the near-field light-matter interaction by tip-enhanced Raman scattering (TERS) with polarized light in three different materials: germanium-doped gallium nitride (GaN), graphene, and carbon nanotubes. We investigate the dependence of the TERS signal on the incoming light polarization and on the sample carrier concentration, as well as the Raman selection rules in the near-field. We explain the experimental data with a tentative quantum mechanical interpretation, which takes into account the role of plasmon polaritons, and the associated evanescent field. The driving force for the breakdown of the classical Raman selection rules in TERS is caused by photon tunneling through the perturbation of the evanescent field, with the consequent polariton annihilation. Predictions based on this quantum mechanical approach are in good agreement with the experimental data, which are shown to be independent of incoming light polarization, leading to new Raman selection rules for TERS.
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Affiliation(s)
- Emanuele Poliani
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
| | - Markus R Wagner
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
| | - Asmus Vierck
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
| | - Felix Herziger
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
| | - Christian Nenstiel
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
| | - Florentina Gannott
- Nanomaterials for Optoelectronics Group, Institute of Polymer Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg , 91054 Erlangen, Germany
| | - Manuel Schweiger
- Nanomaterials for Optoelectronics Group, Institute of Polymer Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg , 91054 Erlangen, Germany
| | - Stephanie Fritze
- Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg , 39106 Magdeburg, Germany
| | - Armin Dadgar
- Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg , 39106 Magdeburg, Germany
| | - Jana Zaumseil
- Physikalisch-Chemisches Institut Lehrstuhl für Angewandte Physikalische Chemie, Ruprecht-Karls-Universität Heidelberg , 69117 Heidelberg, Germany
| | - Alois Krost
- Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg , 39106 Magdeburg, Germany
| | - Axel Hoffmann
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
| | - Janina Maultzsch
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
- Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg , 91054 Erlangen, Germany
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11
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Wang R, Yuan P, Han M, Xu S, Wang T, Wang X. Asymmetry of Raman scattering by structure variation in space. OPTICS EXPRESS 2017; 25:18378-18392. [PMID: 28789324 DOI: 10.1364/oe.25.018378] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 07/18/2017] [Indexed: 06/07/2023]
Abstract
We report on the discovery of asymmetries of Raman scattering along one scanning direction, between two scanning directions, and by structure variation of the sample in space. Asymmetry of Raman shift along the x direction, and the asymmetry of Raman shift and linewidth between the two scanning directions (x and y) are found for a 1210 nm diameter silica particle. The observed asymmetries are confirmed by further 2D Raman scanning of the same particle. To further explore the asymmetry of Raman scattering, glass fibers of three diameters (0.53, 1.00, and 3.20 μm) are scanned along two directions. The asymmetry of Raman shift along each direction, the asymmetry of linewidth along the y direction, and the asymmetry of Raman shift and linewidth between the two scanning directions are discovered. Additionally, 11 nm-thick MoSe2 nanosheets on silicon are used to discover whether an asymmetry of Raman scattering exists at the edge of the nanosheets. One edge of the nanosheet is scanned in four directions and the asymmetry of Raman scattering caused by the step variation is also detected. All the observed Raman scattering asymmetries are explained soundly by the Raman signal diffraction and image shift on the CCD detector arrays of the Raman spectrometer. In practice, to use scanning Raman for surface structure study, great measure has to be taken to consider the structure-induced asymmetries to uncover the real Raman wave number variation by intrinsic material structure. We propose a signal processing method by averaging the scanning points along four directions to eliminate the interference of the edge. This method works well to significantly suppress the asymmetries of Raman properties and uncover the real Raman signal change by structure variation.
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12
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Liu P, Chulhai DV, Jensen L. Single-Molecule Imaging Using Atomistic Near-Field Tip-Enhanced Raman Spectroscopy. ACS NANO 2017; 11:5094-5102. [PMID: 28463555 DOI: 10.1021/acsnano.7b02058] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Advances in tip-enhanced Raman spectroscopy (TERS) have demonstrated ultrahigh spatial resolution so that the vibrational modes of individual molecules can be visualized. The spatial resolution of TERS is determined by the confinement of the plasmon-induced field in the junction; however, the conditions necessary for achieving the high spatial confinement required for imaging individual molecules are not fully understood. Here, we present a systematic theoretical study of TERS imaging of single molecules, using a hybrid atomistic electrodynamics-quantum mechanical method. This approach provides a consistent treatment of the molecule and the plasmonic near field under conditions where they cannot be treated separately. In our simulations, we demonstrate that TERS is capable of resolving intricate molecule vibrations with atomic resolution, although we find that TERS images are extremely sensitive to the near field in the junction. Achieving the atomic resolution requires the near field to be confined within a few ångstroms in diameter and the near-field focal plane to be in the molecule plane. Furthermore, we demonstrate that the traditional surface selection rule of Raman spectroscopy is altered due to the significant field confinement that leads to significant field-gradient effects in the Raman scattering. This work provides insights into single-molecule imaging based on TERS and Raman scattering of molecules in nanojunctions with atomic dimensions.
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Affiliation(s)
- Pengchong Liu
- Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Dhabih V Chulhai
- Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Lasse Jensen
- Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States
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13
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Affiliation(s)
- Weihua Zhang
- College
of Engineering and Applied Sciences, National Laboratory of Solid
State Microstructures, and Collaborative Innovation Center of Advanced
Microstructures, Nanjing University, Nanjing 210093, China
| | - Zheyu Fang
- School
of Physics, State Key Lab for Mesoscopic Physics, and Collaborative
Innovation Center of Quantum Matter, Peking University, Beijing 100871, China
| | - Xing Zhu
- School
of Physics, State Key Lab for Mesoscopic Physics, and Collaborative
Innovation Center of Quantum Matter, Peking University, Beijing 100871, China
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14
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Wang X, Broch K, Schreiber F, Meixner AJ, Zhang D. Revealing nanoscale optical properties and morphology in perfluoropentacene films by confocal and tip-enhanced near-field optical microscopy and spectroscopy. Phys Chem Chem Phys 2016; 18:15919-26. [DOI: 10.1039/c6cp01153e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Combining confocal and high resolution near-field optical microscopy and spectroscopy, we propose a sensitive method for determining the local morphology in organic semiconductor thin films.
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Affiliation(s)
- Xiao Wang
- Institute of Physical and Theoretical Chemistry and LISA+
- University of Tübingen
- 72076 Tübingen
- Germany
| | - Katharina Broch
- Institute of Applied Physics
- University of Tübingen
- 72076 Tübingen
- Germany
- Cavendish Laboratory
| | - Frank Schreiber
- Institute of Applied Physics
- University of Tübingen
- 72076 Tübingen
- Germany
| | - Alfred J. Meixner
- Institute of Physical and Theoretical Chemistry and LISA+
- University of Tübingen
- 72076 Tübingen
- Germany
| | - Dai Zhang
- Institute of Physical and Theoretical Chemistry and LISA+
- University of Tübingen
- 72076 Tübingen
- Germany
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15
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Langelüddecke L, Singh P, Deckert V. Exploring the Nanoscale: Fifteen Years of Tip-Enhanced Raman Spectroscopy. APPLIED SPECTROSCOPY 2015; 69:1357-71. [PMID: 26554759 DOI: 10.1366/15-08014] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Spectroscopic methods with high spatial resolution are essential to understand the physical and chemical properties of nanoscale materials including biological and chemical materials. Tip-enhanced Raman spectroscopy (TERS) is a combination of surface-enhanced Raman spectroscopy (SERS) and scanning probe microscopy (SPM), which can provide high-resolution topographic and spectral information simultaneously below the diffraction limit of light. Even examples of sub-nanometer resolution have been demonstrated. This review intends to give an introduction to TERS, focusing on its basic principle and the experimental setup, the strengths followed by recent applications, developments, and perspectives in this field.
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Affiliation(s)
- Lucas Langelüddecke
- Institute of Physical Chemistry and Abbe Center of Photonics, University of Jena, Helmholtzweg 4, D-07743 Jena, Germany
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16
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Pashaee F, Sharifi F, Fanchini G, Lagugné-Labarthet F. Tip-enhanced Raman spectroscopy of graphene-like and graphitic platelets on ultraflat gold nanoplates. Phys Chem Chem Phys 2015; 17:21315-22. [DOI: 10.1039/c4cp05252h] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
TERS was used to investigate the graphene-like platelets in gap mode geometry using radially and linearly polarized excitation.
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Affiliation(s)
- Farshid Pashaee
- Department of Chemistry
- Department of Physics & Astronomy and Centre for Advanced Materials and Biomaterials Research
- University of Western Ontario
- London
- Canada
| | - Faranak Sharifi
- Department of Chemistry
- Department of Physics and Centre for Advanced Materials and Biomaterials Research
- University of Western Ontario
- London
- Canada
| | - Giovanni Fanchini
- Department of Chemistry
- Department of Physics and Centre for Advanced Materials and Biomaterials Research
- University of Western Ontario
- London
- Canada
| | - François Lagugné-Labarthet
- Department of Chemistry
- Department of Physics & Astronomy and Centre for Advanced Materials and Biomaterials Research
- University of Western Ontario
- London
- Canada
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17
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Chen L, Zhai T, Zhang X, Unger C, Koch J, Chichkov BN, Klar PJ. Polarization-dependent SERS effects of laser-generated sub-100 nm antenna structures. NANOTECHNOLOGY 2014; 25:265302. [PMID: 24915959 DOI: 10.1088/0957-4484/25/26/265302] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Sub-100 nm antenna arrays consisting of a star-like ridge or dome-like structures with needles in their centers are prepared in thin gold films on glass substrates using femtosecond laser pulses. The needles can be bent mechanically to be horizontally aligned to the substrate surface. Controlled variation of the pulse energy allows one to obtain nanostructures of different defined morphologies. These arrays of nanostructures are covered with a thin homogeneous layer of rhodamine molecules. Raman spectra using linearly polarized laser light of 632.8 nm are taken with the laser spot centered on individual nanostructures and at positions on the unstructured film. The average Raman enhancement within the laser spot focused onto a nanostructure is two orders of magnitude higher than on the unstructured film. The nanostructures with bent needles exhibit a polarization dependence of the SERS effect, i.e., typically the enhancement is larger by about a factor of two for excitation light polarized parallel to the needle direction than for the perpendicular case. The enhancement factor of the star-like ridge structures with needles is analyzed by the finite-element method, which agrees with the experiment. We show that the variation of the SERS activity of almost similar structures arises from the inherent randomness of the hot spots created in the fabrication process. Nevertheless, these antenna structures may be useful as elements in novel SERS devices as they can be accurately positioned on a device using a cheap fabrication process compatible with microfabrication technology.
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Affiliation(s)
- Limei Chen
- I. Institute of Physics, Justus-Liebig University of Giessen, Heinrich-Buff-Ring 16, Giessen, D-35392, Germany
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Reichenbach P, Horneber A, Gollmer DA, Hille A, Mihaljevic J, Schäfer C, Kern DP, Meixner AJ, Zhang D, Fleischer M, Eng LM. Nonlinear optical point light sources through field enhancement at metallic nanocones. OPTICS EXPRESS 2014; 22:15484-501. [PMID: 24977808 DOI: 10.1364/oe.22.015484] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
A stable nonlinear optical point light source is investigated, based on field enhancement at individual, pointed gold nanocones with sub-wavelength dimensions. Exciting these cones with near-infrared, focused radially polarized femtosecond beams allows for tip-emission at the second harmonic wavelength (second harmonic generation, SHG) in the visible range. In fact, gold nanocones with ultra-sharp tips possess interesting nonlinear optical (NLO) properties for SHG and two-photon photoluminescence (TPPL) emission, due to the enhanced electric field confinement at the tip apex combined with centrosymmetry breaking. Using two complementary optical setups for bottom or top illumination a sharp tip SHG emission is discriminated from the broad TPPL background continuum. Moreover, comparing the experiments with theoretical calculations manifests that these NLO signatures originate either from the tip apex or the base edge of the nanocones, clearly depending on the cone size, the surrounding medium, and illumination conditions. Finally, it is demonstrated that the tip-emitted signal vanishes when switching from radial to azimuthal polarization.
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Awez Mohammad A, Arnott ZL, Wang Y, Kruse P. Note: benign and reproducible preparation of titanium tips. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:026113. [PMID: 24593413 DOI: 10.1063/1.4865759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Fabrication of titanium tips via electrochemical etching is commonly hindered by the formation of a tough oxide layer. A new one-step approach based on dc etching in a non-aqueous electrolyte is presented. The electrochemical tip etching was carried out at 20 V in a benign etchant of 1M NaCl in ethylene glycol. Tip radii below 100 nm are demonstrated using current cut-off control and approaching 150 nm without cut-off control. The simplicity and efficiency of the approach eliminates pre and post electropolishing steps due to the electropolishing capability of a NaCl-ethylene glycol based electrolyte.
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Affiliation(s)
- A Awez Mohammad
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario L8S 4M1, Canada
| | - Z L Arnott
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario L8S 4M1, Canada
| | - Y Wang
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario L8S 4M1, Canada
| | - P Kruse
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario L8S 4M1, Canada
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Sasaki SS, Perdue SM, Rodriguez Perez A, Tallarida N, Majors JH, Apkarian VA, Lee J. Note: Automated electrochemical etching and polishing of silver scanning tunneling microscope tips. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:096109. [PMID: 24089884 DOI: 10.1063/1.4822115] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Fabrication of sharp and smooth Ag tips is crucial in optical scanning probe microscope experiments. To ensure reproducible tip profiles, the polishing process is fully automated using a closed-loop laminar flow system to deliver the electrolytic solution to moving electrodes mounted on a motorized translational stage. The repetitive translational motion is controlled precisely on the μm scale with a stepper motor and screw-thread mechanism. The automated setup allows reproducible control over the tip profile and improves smoothness and sharpness of tips (radius 27 ± 18 nm), as measured by ultrafast field emission.
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Affiliation(s)
- Stephen S Sasaki
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, USA
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Schmid T, Opilik L, Blum C, Zenobi R. Chemische Bildgebung auf der Nanometerskala mittels spitzenverstärkter Raman-Spektroskopie. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201203849] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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22
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Schmid T, Opilik L, Blum C, Zenobi R. Nanoscale Chemical Imaging Using Tip-Enhanced Raman Spectroscopy: A Critical Review. Angew Chem Int Ed Engl 2013; 52:5940-54. [DOI: 10.1002/anie.201203849] [Citation(s) in RCA: 250] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 09/02/2012] [Indexed: 11/12/2022]
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Kravtsov V, Atkin JM, Raschke MB. Group delay and dispersion in adiabatic plasmonic nanofocusing. OPTICS LETTERS 2013; 38:1322-4. [PMID: 23595472 DOI: 10.1364/ol.38.001322] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We study the decrease in group velocity of broadband surface plasmon polariton propagation on a conical tip, using femtosecond time-domain interferometry. The group delay of (9±3) fs measured corresponds to a group velocity at the apex of less than 0.2c. The result agrees in general with the prediction from adiabatic plasmonic nanofocusing theory, yet is sensitive with respect to the exact taper geometry near the apex. This, together with the sub 25 fs(2) second-order dispersion observed, provides the fundamental basis for the use of plasmons for broadband slow-light applications.
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Affiliation(s)
- Vasily Kravtsov
- Department of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder, Colorado 80309, USA
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Hermann P, Hermelink A, Lausch V, Holland G, Möller L, Bannert N, Naumann D. Evaluation of tip-enhanced Raman spectroscopy for characterizing different virus strains. Analyst 2011; 136:1148-52. [DOI: 10.1039/c0an00531b] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Anderson A, Deryckx KS, Xu XG, Steinmeyer G, Raschke MB. Few-femtosecond plasmon dephasing of a single metallic nanostructure from optical response function reconstruction by interferometric frequency resolved optical gating. NANO LETTERS 2010; 10:2519-24. [PMID: 20518538 DOI: 10.1021/nl101090s] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The precise characterization of the ultrafast optical response of metals and metallic nanostructures has remained an experimental challenge. We probe the few-femtosecond electronic dephasing of a local surface plasmon polariton excitation using symmetry-selective second-harmonic (SH) Rayleigh scattering of a nanoscopic conical gold tip as an individual plasmonic nanostructure. The full reconstruction of the optical response function of the plasmon excitation with phase and amplitude without any model assumptions is demonstrated from the analysis of the two-dimensional spectrogram obtained by simultaneous time- and frequency-domain SH measurements, using interferometric frequency resolved optical gating. The measured dephasing time of T(2) = 18 +/- 5 fs indicates the plasmon damping is dominated by nonradiative decay, consistent with a Drude-Sommerfeld dielectric response for gold. Even for the nominally homogeneous localized plasmon response, deviations are observed from the ideal harmonic oscillator phase behavior, which may reflect the underlying inhomogeneous electronic response with its different scattering channels. The presented technique is generally applicable for the reconstruction of the plasmon dynamics of complex nanostructures: information that cannot be obtained by conventional dark-field scattering.
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Affiliation(s)
- Alexandria Anderson
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
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Berweger S, Raschke MB. Signal limitations in tip-enhanced Raman scattering: the challenge to become a routine analytical technique. Anal Bioanal Chem 2009; 396:115-23. [DOI: 10.1007/s00216-009-3085-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Revised: 08/18/2009] [Accepted: 08/19/2009] [Indexed: 11/28/2022]
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