1
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Qiang Y, Sun K, Palacino-González E, Shen K, Rao BJ, Gelin MF, Zhao Y. Probing avoided crossings and conical intersections by two-pulse femtosecond stimulated Raman spectroscopy: Theoretical study. J Chem Phys 2024; 160:054107. [PMID: 38341700 DOI: 10.1063/5.0186583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 01/15/2024] [Indexed: 02/13/2024] Open
Abstract
This study leverages two-pulse femtosecond stimulated Raman spectroscopy (2FSRS) to characterize molecular systems with avoided crossings (ACs) and conical intersections (CIs) in their low-lying excited electronic states. By simulating 2FSRS spectra of microscopically inspired ACs and CIs models, we demonstrate that 2FSRS not only delivers valuable information on the molecular parameters characterizing ACs and CIs but also helps distinguish between these two systems.
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Affiliation(s)
- Yijia Qiang
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Kewei Sun
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Elisa Palacino-González
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Kaijun Shen
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - B Jayachander Rao
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Maxim F Gelin
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Yang Zhao
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
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2
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Lynch P, Das A, Alam S, Rich CC, Frontiera RR. Mastering Femtosecond Stimulated Raman Spectroscopy: A Practical Guide. ACS PHYSICAL CHEMISTRY AU 2024; 4:1-18. [PMID: 38283786 PMCID: PMC10811773 DOI: 10.1021/acsphyschemau.3c00031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/02/2023] [Accepted: 10/02/2023] [Indexed: 01/30/2024]
Abstract
Femtosecond stimulated Raman spectroscopy (FSRS) is a powerful nonlinear spectroscopic technique that probes changes in molecular and material structure with high temporal and spectral resolution. With proper spectral interpretation, this is equivalent to mapping out reactive pathways on highly anharmonic excited-state potential energy surfaces with femtosecond to picosecond time resolution. FSRS has been used to examine structural dynamics in a wide range of samples, including photoactive proteins, photovoltaic materials, plasmonic nanostructures, polymers, and a range of others, with experiments performed in multiple groups around the world. As the FSRS technique grows in popularity and is increasingly implemented in user facilities, there is a need for a widespread understanding of the methodology and best practices. In this review, we present a practical guide to FSRS, including discussions of instrumentation, as well as data acquisition and analysis. First, we describe common methods of generating the three pulses required for FSRS: the probe, Raman pump, and actinic pump, including a discussion of the parameters to consider when selecting a beam generation method. We then outline approaches for effective and efficient FSRS data acquisition. We discuss common data analysis techniques for FSRS, as well as more advanced analyses aimed at extracting small signals on a large background. We conclude with a discussion of some of the new directions for FSRS research, including spectromicroscopy. Overall, this review provides researchers with a practical handbook for FSRS as a technique with the aim of encouraging many scientists and engineers to use it in their research.
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Affiliation(s)
- Pauline
G. Lynch
- Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Aritra Das
- Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Shahzad Alam
- Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Christopher C. Rich
- Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Renee R. Frontiera
- Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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3
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Mandal A, Ziegler LD. Vibrational line shape effects in plasmon-enhanced stimulated Raman spectroscopies. J Chem Phys 2021; 155:194701. [PMID: 34800946 DOI: 10.1063/5.0067301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A density matrix treatment of plasmon-enhanced (PE) stimulated Raman spectroscopies is developed. Specifically, PE stimulated Raman Gain/Loss (PE-SRG/L) and coherent anti-Stokes Raman scattering (PE-CARS) due to monochromatic excitation and PE femtosecond stimulated Raman spectroscopy (PE-FSRS) are considered. A Lorentz oscillator model is used to explicitly describe the time dependence of plasmon-enhanced optical fields. These temporal characteristics are required for a density matrix based description of all plasmon-enhanced nonlinear molecular spectroscopies. Dispersive vibrational line shapes in PE-SRG/L and PE-FSRS spectra are shown to result primarily from terms proportional to the square of the complex optical field enhancement factor. The dependence on the plasmon resonance, picosecond and femtosecond pulse characteristics, and molecular vibrational properties are evident in the density matrix derived PE-FSRS intensity expression. The difference in signal detection mechanisms accounts for the lack of dispersive line shapes in PE spontaneous Raman spectroscopy. This density matrix treatment of PE-FSRS line shapes is compared with prior coupled wave results.
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Affiliation(s)
- Aritra Mandal
- Intel Corporation, 2501 NW 229th Ave., Hillsboro, Oregon 97124, USA
| | - L D Ziegler
- Department of Chemistry, Photonics Center Boston University, Boston, Massachusetts 02215, USA
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4
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Warkentin CL, Yu Z, Sarkar A, Frontiera RR. Decoding Chemical and Physical Processes Driving Plasmonic Photocatalysis Using Surface-Enhanced Raman Spectroscopies. Acc Chem Res 2021; 54:2457-2466. [PMID: 33957039 DOI: 10.1021/acs.accounts.1c00088] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In order to mitigate the advancing effects of environmental pollution and climate change, immediate action is needed on social, political, and industrial fronts. One segment of industry that contributes significantly to this current crisis is bulk chemical production, where fossil fuels are primarily used to drive reactions at high temperatures and pressures. Toward mitigating the environmental impact of these processes, solar energy has shown promise as a clean and renewable alternative for the photocatalytic synthesis of chemicals. In recent decades, plasmonic materials have emerged as candidates for making this a reality. Because of their unique and tunable interactions with light, plasmonic materials can be used to create energy-rich nanoscale environments. In fact, there is a growing library of chemical reactions that can utilize this plasmonic energy to drive industrially relevant chemistries under standard ambient conditions. However, the efficiency of these reactions is typically low, and a lack of mechanistic understanding of how energy is transferred from plasmons to molecules hinders reaction optimization for use on large scales.To decode the complex chemical and physical processes involved in plasmon-driven photocatalytic reactions, we use surface-enhanced Raman spectroscopy (SERS). In this Account, we detail SERS techniques that we have used and are developing to study molecular transformations, charge transfer, and plasmonic heating in dynamic plasmon-molecule systems on time scales ranging from seconds to femtoseconds. SERS is an ideal analytical tool for understanding plasmon-molecule interactions, as it gives highly specific information about molecular vibrations with high sensitivity, down to the single-molecule level. Importantly, SERS allows for simultaneous pumping of a plasmonic resonance and probing of the enhanced Raman signal from nearby molecules. We have already used these techniques to study a plasmon-driven methyl migration with nanoscale spatial specificity and to understand the charge transfer mechanism and role of heating in the plasmon-mediated dimerization of 4-nitrobenzenethiol. Importantly, from this work we conclude that direct charge transfer, not heating, may play a significant role in driving many plasmon-driven reactions. Despite these recent insights, more work is needed in order to obtain a comprehensive understanding of the broad range of chemistries accessible in plasmon-molecule systems. In the future, our continued development of these SERS-based techniques shows promise in answering questions regarding direct charge transfer, resonance energy transfer, and excitation conditions in plasmon-mediated chemistries.
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Affiliation(s)
| | - Ziwei Yu
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Arghya Sarkar
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Renee R. Frontiera
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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5
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Zong C, Xie Y, Zhang M, Huang Y, Yang C, Cheng JX. Plasmon-enhanced coherent anti-stokes Raman scattering vs plasmon-enhanced stimulated Raman scattering: Comparison of line shape and enhancement factor. J Chem Phys 2021; 154:034201. [PMID: 33499625 PMCID: PMC7816769 DOI: 10.1063/5.0035163] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 12/28/2020] [Indexed: 12/12/2022] Open
Abstract
Plasmon-enhanced coherent Raman scattering microscopy has reached single-molecule detection sensitivity. Due to the different driven fields, there are significant differences between a coherent Raman scattering process and its plasmon-enhanced derivative. The commonly accepted line shapes for coherent anti-Stokes Raman scattering and stimulated Raman scattering do not hold for the plasmon-enhanced condition. Here, we present a theoretical model that describes the spectral line shapes in plasmon-enhanced coherent anti-Stokes Raman scattering (PECARS). Experimentally, we measured PECARS and plasmon-enhanced stimulated Raman scattering (PESRS) spectra of 4-mercaptopyridine adsorbed on the self-assembled Au nanoparticle (NP) substrate and aggregated Au NP colloids. The PECARS spectra show a nondispersive line shape, while the PESRS spectra exhibit a dispersive line shape. PECARS shows a higher signal to noise ratio and a larger enhancement factor than PESRS from the same specimen. It is verified that the nonresonant background in PECARS originates from the photoluminescence of nanostructures. The decoupling of background and the vibrational resonance component results in the nondispersive line shape in PECARS. More local electric field enhancements are involved in the PECARS process than in PESRS, which results in a higher enhancement factor in PECARS. The current work provides new insight into the mechanism of plasmon-enhanced coherent Raman scattering and helps to optimize the experimental design for ultrasensitive chemical imaging.
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Affiliation(s)
- Cheng Zong
- Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Yurun Xie
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Meng Zhang
- Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215, USA
| | - Yimin Huang
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA
| | | | - Ji-Xin Cheng
- Author to whom correspondence should be addressed:
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6
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Sartin MM, Su HS, Wang X, Ren B. Tip-enhanced Raman spectroscopy for nanoscale probing of dynamic chemical systems. J Chem Phys 2020; 153:170901. [PMID: 33167627 DOI: 10.1063/5.0027917] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Dynamics are fundamental to all aspects of chemistry and play a central role in the mechanism and product distribution of a chemical reaction. All dynamic processes are influenced by the local environment, so it is of fundamental and practical value to understand the structure of the environment and the dynamics with nanoscale resolution. Most techniques for measuring dynamic processes have microscopic spatial resolution and can only measure the average behavior of a large ensemble of sites within their sampling volumes. Tip-enhanced Raman spectroscopy (TERS) is a powerful tool for overcoming this limitation due to its combination of high chemical specificity and spatial resolution that is on the nanometer scale. Adapting it for the study of dynamic systems remains a work in progress, but the increasing sophistication of TERS is making such studies more routine, and there are now growing efforts to use TERS to examine more complex processes. This Perspective aims to promote development in this area of research by highlighting recent progress in using TERS to understand reacting and dynamic systems, ranging from simple model reactions to complex processes with practical applications. We discuss the unique challenges and opportunities that TERS presents for future studies.
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Affiliation(s)
- Matthew M Sartin
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Hai-Sheng Su
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiang Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Bin Ren
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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7
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Zong C, Premasiri R, Lin H, Huang Y, Zhang C, Yang C, Ren B, Ziegler LD, Cheng JX. Plasmon-enhanced stimulated Raman scattering microscopy with single-molecule detection sensitivity. Nat Commun 2019; 10:5318. [PMID: 31754221 PMCID: PMC6872561 DOI: 10.1038/s41467-019-13230-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 10/22/2019] [Indexed: 12/27/2022] Open
Abstract
Stimulated Raman scattering (SRS) microscopy allows for high-speed label-free chemical imaging of biomedical systems. The imaging sensitivity of SRS microscopy is limited to ~10 mM for endogenous biomolecules. Electronic pre-resonant SRS allows detection of sub-micromolar chromophores. However, label-free SRS detection of single biomolecules having extremely small Raman cross-sections (~10-30 cm2 sr-1) remains unreachable. Here, we demonstrate plasmon-enhanced stimulated Raman scattering (PESRS) microscopy with single-molecule detection sensitivity. Incorporating pico-Joule laser excitation, background subtraction, and a denoising algorithm, we obtain robust single-pixel SRS spectra exhibiting single-molecule events, verified by using two isotopologues of adenine and further confirmed by digital blinking and bleaching in the temporal domain. To demonstrate the capability of PESRS for biological applications, we utilize PESRS to map adenine released from bacteria due to starvation stress. PESRS microscopy holds the promise for ultrasensitive detection and rapid mapping of molecular events in chemical and biomedical systems.
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Affiliation(s)
- Cheng Zong
- Department of Electrical and Computer Engineering, Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA.,State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, 361005, Xiamen, China
| | - Ranjith Premasiri
- Department of Chemistry, Boston University, Boston, MA, 02215, USA.,Photonics Center, Boston University, Boston, MA, 02215, USA
| | - Haonan Lin
- Department of Electrical and Computer Engineering, Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Yimin Huang
- Department of Chemistry, Boston University, Boston, MA, 02215, USA
| | - Chi Zhang
- Department of Electrical and Computer Engineering, Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Chen Yang
- Department of Chemistry, Boston University, Boston, MA, 02215, USA.,Photonics Center, Boston University, Boston, MA, 02215, USA
| | - Bin Ren
- State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, 361005, Xiamen, China
| | - Lawrence D Ziegler
- Department of Chemistry, Boston University, Boston, MA, 02215, USA.,Photonics Center, Boston University, Boston, MA, 02215, USA
| | - Ji-Xin Cheng
- Department of Electrical and Computer Engineering, Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA. .,Department of Chemistry, Boston University, Boston, MA, 02215, USA. .,Photonics Center, Boston University, Boston, MA, 02215, USA.
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8
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Henry AI, Ueltschi TW, McAnally MO, Van Duyne RP. Spiers Memorial Lecture. Surface-enhanced Raman spectroscopy: from single particle/molecule spectroscopy to ångstrom-scale spatial resolution and femtosecond time resolution. Faraday Discuss 2019; 205:9-30. [PMID: 28906524 DOI: 10.1039/c7fd00181a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Four decades on, surface-enhanced Raman spectroscopy (SERS) continues to be a vibrant field of research that is growing (approximately) exponentially in scope and applicability while pushing at the ultimate limits of sensitivity, spatial resolution, and time resolution. This introductory paper discusses some aspects related to all four of the themes for this Faraday Discussion. First, the wavelength-scanned SERS excitation spectroscopy (WS-SERES) of single nanosphere oligomers (viz., dimers, trimers, etc.), the distance dependence of SERS, the magnitude of the chemical enhancement mechanism, and the progress toward developing surface-enhanced femtosecond stimulated Raman spectroscopy (SE-FSRS) are discussed. Second, our efforts to develop a continuous, minimally invasive, in vivo glucose sensor based on SERS are highlighted. Third, some aspects of our recent work in single molecule SERS and the translation of that effort to ångstrom-scale spatial resolution in ultrahigh vacuum tip-enhanced Raman spectroscopy (UHV-TERS) and single molecule electrochemistry using electrochemical (EC)-TERS will be presented. Finally, we provide an overview of analytical SERS with our viewpoints on SERS substrates, approaches to address the analyte generality problem (i.e. target molecules that do not spontaneously adsorb and/or have Raman cross sections <10-29 cm2 sr-1), SERS for catalysis, and deep UV-SERS.
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Affiliation(s)
- Anne-Isabelle Henry
- Departments of Chemistry, Biomedical Engineering, and Applied Physics, Northwestern University, Evanston, IL 60208-3113, USA.
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9
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Tamma VA, Beecher LM, Shumaker-Parry JS, Wickramasinghe HK. Detecting stimulated Raman responses of molecules in plasmonic gap using photon induced forces. OPTICS EXPRESS 2018; 26:31439-31453. [PMID: 30650729 DOI: 10.1364/oe.26.031439] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 11/06/2018] [Indexed: 06/09/2023]
Abstract
We demonstrate the stimulated Raman nanoscopy of a small number of molecules in a plasmonic gap, excited without resonant electronic enhancement, measured using near-field photon-induced forces, eliminating the need for far-field optical detection. We imaged 30 nm diameter gold nanoparticles functionalized with a self-assembled monolayer (SAM) of 4-nitrobenzenethiol (4-NBT) molecules. The maximum number of molecules detected by the gold-coated nano-probe at the position of maximum field enhancement could be fewer than about 42 molecules. The molecules were imaged by vibrating an Atomic Force Microscope (AFM) cantilever on its second flexural eigenmode enabling the tip to be controlled much closer to the sample, thereby improving the detected signal-to-noise ratio when compared to vibrating the cantilever on its first flexural eigenmode. We also demonstrate the implementation of stimulated Raman nanoscopy measured using photon-induced force with non-collinear pump and stimulating beams which could have applications in polarization dependent Raman nanoscopy and spectroscopy and pump-probe nano-spectroscopy particularly involving infrared beam/s. We also discuss using photon induced forces as a technique to sort and select best performing metal coated tips for further use in tip-enhanced experiments.
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10
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Shi L, Xiong H, Shen Y, Long R, Wei L, Min W. Electronic Resonant Stimulated Raman Scattering Micro-Spectroscopy. J Phys Chem B 2018; 122:9218-9224. [PMID: 30208710 DOI: 10.1021/acs.jpcb.8b07037] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recently we have reported electronic pre-resonance stimulated Raman scattering (epr-SRS) microscopy as a powerful technique for super-multiplex imaging ( Wei, L. ; Nature 2017 , 544 , 465 - 470 ). However, under rigorous electronic resonance, background signal, which mainly originates from pump-probe process, overwhelms the desired vibrational signature of the chromophores. Here we demonstrate electronic resonant stimulated Raman scattering (er-SRS) microspectroscopy and imaging through suppression of electronic background and subsequent retrieval of vibrational peaks. We observed a change of the vibrational band shapes from normal Lorentzian, through dispersive shapes, to inverted Lorentzian as the electronic resonance was approached, in agreement with theoretical prediction. In addition, resonant Raman cross sections have been determined after power-dependence study as well as Raman excitation profile calculation. As large as 10-23 cm2 of resonance Raman cross section is estimated in er-SRS, which is about 100 times higher than previously reported in epr-SRS. These results of er-SRS microspectroscopy pave the way for the single-molecule Raman detection and ultrasensitive biological imaging.
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Affiliation(s)
- Lixue Shi
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Hanqing Xiong
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Yihui Shen
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Rong Long
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Lu Wei
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Wei Min
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
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11
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Ashner MN, Tisdale WA. High repetition-rate femtosecond stimulated Raman spectroscopy with fast acquisition. OPTICS EXPRESS 2018; 26:18331-18340. [PMID: 30114014 DOI: 10.1364/oe.26.018331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/27/2018] [Indexed: 06/08/2023]
Abstract
Time-resolved femtosecond stimulated Raman spectroscopy (FSRS) is a powerful tool for investigating ultrafast structural and vibrational dynamics in light absorbing systems. However, the technique generally requires exposing a sample to high laser pulse fluences and long acquisition times to achieve adequate signal-to-noise ratios. Here, we describe a time-resolved FSRS instrument built around a Yb ultrafast amplifier operating at 200 kHz, and address some of the unique challenges that arise at high repetition-rates. The setup includes detection with a 9 kHz CMOS camera and an improved dual-chopping scheme to reject scattering artifacts that occur in the 3-pulse configuration. The instrument demonstrates good signal-to-noise performance while simultaneously achieving a 3-6 fold reduction in pulse energy and a 5-10 fold reduction in acquisition time relative to comparable 1 kHz instruments.
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12
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Fang C, Tang L, Oscar BG, Chen C. Capturing Structural Snapshots during Photochemical Reactions with Ultrafast Raman Spectroscopy: From Materials Transformation to Biosensor Responses. J Phys Chem Lett 2018; 9:3253-3263. [PMID: 29799757 DOI: 10.1021/acs.jpclett.8b00373] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Chemistry studies the composition, structure, properties, and transformation of matter. A mechanistic understanding of the pertinent processes is required to translate fundamental knowledge into practical applications. The current development of ultrafast Raman as a powerful time-resolved vibrational technique, particularly femtosecond stimulated Raman spectroscopy (FSRS), has shed light on the structure-energy-function relationships of various photosensitive systems. This Perspective reviews recent work incorporating optical innovations, including the broad-band up-converted multicolor array (BUMA) into a tunable FSRS setup, and demonstrates its resolving power to watch metal speciation and photolysis, leading to high-quality thin films, and fluorescence modulation of chimeric protein biosensors for calcium ion imaging. We discuss advantages of performing FSRS in the mixed time-frequency domain and present strategies to delineate mechanisms by tracking low-frequency modes and systematically modifying chemical structures with specific functional groups. These unique insights at the chemical-bond level have started to enable the rational design and precise control of functional molecular machines in optical, materials, energy, and life sciences.
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Affiliation(s)
- Chong Fang
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
| | - Longteng Tang
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
| | - Breland G Oscar
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
| | - Cheng Chen
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
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13
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Buchanan LE, McAnally MO, Gruenke NL, Schatz GC, Van Duyne RP. Studying Stimulated Raman Activity in Surface-Enhanced Femtosecond Stimulated Raman Spectroscopy by Varying the Excitation Wavelength. J Phys Chem Lett 2017; 8:3328-3333. [PMID: 28679047 DOI: 10.1021/acs.jpclett.7b01342] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present the first multiwavelength surface-enhanced femtosecond stimulated Raman spectroscopy (SE-FSRS) study, as well as the first observation of anti-Stokes vibrational features in SE-FSRS spectra. We compare stimulated Raman loss (SRL) and stimulated Raman gain (SRG) signals at three pump wavelengths chosen to sample different portions of nanoparticle aggregate localized surface plasmon resonances. The SE-FSRS signals exhibit similar signal magnitudes in the SRL or SRG regions of the spectra regardless of Raman pump or probe wavelength. The spectral lineshapes, however, differ dramatically with excitation wavelengths. The observed trends in spectral line shape show a strong dependence on the relative position of the excitation fields with respect to the plasmon resonance but do not match predictions from any existing SE-FSRS theory. These results suggest the need for further theoretical efforts with complementary experimental studies of individual aggregates to remove the effects of inherent ensemble averaging.
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Affiliation(s)
- Lauren E Buchanan
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Michael O McAnally
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Natalie L Gruenke
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - George C Schatz
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Richard P Van Duyne
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
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14
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Gandman A, Mackin R, Cohn B, Rubtsov IV, Chuntonov L. Two-Dimensional Fano Lineshapes in Ultrafast Vibrational Spectroscopy of Thin Molecular Layers on Plasmonic Arrays. J Phys Chem Lett 2017; 8:3341-3346. [PMID: 28677974 DOI: 10.1021/acs.jpclett.7b01490] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Two-dimensional femtosecond infrared (2DIR) spectroscopy routinely provides insights into molecular structure and ultrafast dynamics in 1-100 μm thick bulk samples. Confinement of molecules to surfaces, gaps, crevices, and other topographic features, frequently encountered on the nanometer length scale, significantly alters their structure and dynamics, affecting physical and chemical properties. Amplification of 2DIR signals by the plasmon-enhanced fields around metal nanostructures can permit structural and dynamics measurements of the confined molecules. Fano resonances, induced by the interaction between laser pulses, plasmon, and vibrational modes significantly distort 2D lineshapes. For different detuning from plasmon resonance, the interference between multiple signal components leads to different line shape asymmetry, which we demonstrate on a set of linear absorption, transient absorption, and 2DIR spectra. An intuitive model used to describe experimental data points to the interference's origin. Our results will facilitate the application of surface-enhanced 2DIR spectroscopy for studies of molecular structure and dynamics in a nanoconfined environment.
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Affiliation(s)
- Andrey Gandman
- Solid State Institute, Technion - Israel Institute of Technology , Haifa 32000, Israel
| | - Robert Mackin
- Department of Chemistry, Tulane University , New Orleans, Louisiana 70118, United States
| | - Bar Cohn
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology , Haifa 32000, Israel
| | - Igor V Rubtsov
- Department of Chemistry, Tulane University , New Orleans, Louisiana 70118, United States
| | - Lev Chuntonov
- Solid State Institute, Technion - Israel Institute of Technology , Haifa 32000, Israel
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology , Haifa 32000, Israel
- Russel Berrie Nanotechnology Institute, Technion - Israel Institute of Technology , Haifa 32000, Israel
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15
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Ding SY, You EM, Tian ZQ, Moskovits M. Electromagnetic theories of surface-enhanced Raman spectroscopy. Chem Soc Rev 2017; 46:4042-4076. [DOI: 10.1039/c7cs00238f] [Citation(s) in RCA: 734] [Impact Index Per Article: 104.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A fundamental theoretical understanding of SERS, and SERS hotspots, leads to new design principles for SERS substrates and new applications in nanomaterials and chemical analysis.
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Affiliation(s)
- Song-Yuan Ding
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS)
- Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - En-Ming You
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS)
- Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Zhong-Qun Tian
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS)
- Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Martin Moskovits
- Department of Chemistry and Biochemistry
- University of California
- Santa Barbara
- California
- USA
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