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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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2
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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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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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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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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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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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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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Abstract
Stimulated Raman scattering (SRS) describes a family of techniques first discovered and developed in the 1960s. Whereas the nascent history of the technique is parallel to that of laser light sources, recent advances have spurred a resurgence in its use and development that has spanned across scientific fields and spatial scales. SRS is a nonlinear technique that probes the same vibrational modes of molecules that are seen in spontaneous Raman scattering. While spontaneous Raman scattering is an incoherent technique, SRS is a coherent process, and this fact provides several advantages over conventional Raman techniques, among which are much stronger signals and the ability to time-resolve the vibrational motions. Technological improvements in pulse generation and detection strategies have allowed SRS to probe increasingly smaller volumes and shorter time scales. This has enabled SRS research to move from its original domain, of probing bulk media, to imaging biological tissues and single cells at the micro scale, and, ultimately, to characterizing samples with subdiffraction resolution at the nanoscale. In this Review, we give an overview of the history of the technique, outline its basic properties, and present historical and current uses at multiple length scales to underline the utility of SRS to the molecular sciences.
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Affiliation(s)
- Richard C Prince
- Department of Biomedical Engineering, University of California, Irvine , 1436 Natural Sciences II, Irvine, California 92697-2025, United States
| | - Renee R Frontiera
- Department of Chemistry, University of Minnesota, Minneapolis , B-18, 139 Smith Hall, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Eric O Potma
- Department of Chemistry, University of California, Irvine , 1107 Natural Sciences II, Irvine, California 92697-2025, United States
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Buchanan LE, Gruenke NL, McAnally MO, Negru B, Mayhew HE, Apkarian VA, Schatz GC, Van Duyne RP. Surface-Enhanced Femtosecond Stimulated Raman Spectroscopy at 1 MHz Repetition Rates. J Phys Chem Lett 2016; 7:4629-4634. [PMID: 27802054 DOI: 10.1021/acs.jpclett.6b02175] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Surface-enhanced femtosecond stimulated Raman spectroscopy (SE-FSRS) is an ultrafast Raman technique that combines the sensitivity of surface-enhanced Raman scattering with the temporal resolution of femtosecond stimulated Raman spectroscopy (FSRS). Here, we present the first successful implementation of SE-FSRS using a 1 MHz amplified femtosecond laser system. We compare SE-FSRS and FSRS spectra measured at 1 MHz and 100 kHz using both equal pump average powers and equal pump energies to demonstrate that higher repetition rates allow spectra with higher signal-to-noise ratios to be obtained at lower pulse energies, a significant advance in the implementation of SE-FSRS. The ability to use lower pulse energies significantly mitigates sample damage that results from plasmonic enhancement of high-energy ultrafast pulses. As a result of the improvements to SE-FSRS developed in this Letter, we believe that SE-FSRS is now poised to become a powerful tool for studying the dynamics of plasmonic materials and adsorbates thereon.
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Affiliation(s)
- Lauren E Buchanan
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Natalie L Gruenke
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Michael O McAnally
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Bogdan Negru
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Hannah E Mayhew
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Vartkess A Apkarian
- Department of Chemistry, University of California-Irvine , Irvine, California 92697, 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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