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Falvo C, Li H. Double-quantum spectroscopy of dense atomic vapors: Interplay between Doppler and self-broadenings. J Chem Phys 2023; 159:064304. [PMID: 37578061 DOI: 10.1063/5.0158307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 07/11/2023] [Indexed: 08/15/2023] Open
Abstract
In this article, we present a simulation study of the linear and nonlinear spectroscopy of dense atomic vapors. Motivated by recent experiments, we focus on double quantum spectroscopy, which directly probes dipole-dipole interactions. By explicitly including thermal velocity, we show that temperature has an important impact on the self-broadening mechanisms of the linear and nonlinear spectra. We also provide analytical expressions for the response functions in the short time limit using the two-body approximation, which shows that double quantum spectroscopy for atomic vapors directly probes the transition amplitude of the electronic excitation between two atoms. We also propose an expression for the double quantum spectrum that includes the effect of Doppler broadening, and we discuss the effect of density on the spectrum. We show that when Doppler broadening is negligible compared to self-broadening, the double quantum spectrum scales with the atomic density, while when Doppler broadening dominates, it scales as the square of the density.
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Affiliation(s)
- Cyril Falvo
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France
- Université Grenoble-Alpes, CNRS, LIPhy, 38000 Grenoble, France
| | - Hebin Li
- Department of Physics, Florida International University, Miami, Florida 33199, USA
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Bangert U, Bruder L, Stienkemeier F. Pulse overlap ambiguities in multiple quantum coherence spectroscopy. OPTICS LETTERS 2023; 48:538-541. [PMID: 36723525 DOI: 10.1364/ol.479881] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 12/21/2022] [Indexed: 06/18/2023]
Abstract
Coherent two-dimensional electronic spectroscopy probes ultrafast dynamics using femtosecond pulses. In the case where the time scale of the studied dynamics become comparable to the pulse duration, pulse overlap effects may compromise the experimental data. Here, we perform one-dimensional coherence scans and study pulse overlap effects in clean two-level systems. We find parasitic multiple-quantum coherences as a consequence of the arbitrary time ordering during the temporal pulse overlap. Surprisingly, the coherence lifetimes exceed the pulse coherence time by a factor of 1.85. These findings have important implications for the interpretation of higher-order coherent two-dimensional and related spectroscopy experiments.
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Gelin MF, Chen L, Domcke W. Equation-of-Motion Methods for the Calculation of Femtosecond Time-Resolved 4-Wave-Mixing and N-Wave-Mixing Signals. Chem Rev 2022; 122:17339-17396. [PMID: 36278801 DOI: 10.1021/acs.chemrev.2c00329] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Femtosecond nonlinear spectroscopy is the main tool for the time-resolved detection of photophysical and photochemical processes. Since most systems of chemical interest are rather complex, theoretical support is indispensable for the extraction of the intrinsic system dynamics from the detected spectroscopic responses. There exist two alternative theoretical formalisms for the calculation of spectroscopic signals, the nonlinear response-function (NRF) approach and the spectroscopic equation-of-motion (EOM) approach. In the NRF formalism, the system-field interaction is assumed to be sufficiently weak and is treated in lowest-order perturbation theory for each laser pulse interacting with the sample. The conceptual alternative to the NRF method is the extraction of the spectroscopic signals from the solutions of quantum mechanical, semiclassical, or quasiclassical EOMs which govern the time evolution of the material system interacting with the radiation field of the laser pulses. The NRF formalism and its applications to a broad range of material systems and spectroscopic signals have been comprehensively reviewed in the literature. This article provides a detailed review of the suite of EOM methods, including applications to 4-wave-mixing and N-wave-mixing signals detected with weak or strong fields. Under certain circumstances, the spectroscopic EOM methods may be more efficient than the NRF method for the computation of various nonlinear spectroscopic signals.
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Affiliation(s)
- Maxim F Gelin
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Lipeng Chen
- Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Strasse 38, D-01187 Dresden, Germany
| | - Wolfgang Domcke
- Department of Chemistry, Technical University of Munich, D-85747 Garching,Germany
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Liang D, Savio Rodriguez L, Zhou H, Zhu Y, Li H. Optical two-dimensional coherent spectroscopy of cold atoms. OPTICS LETTERS 2022; 47:6452-6455. [PMID: 36538460 DOI: 10.1364/ol.478793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
We report an experimental demonstration of optical two-dimensional coherent spectroscopy (2DCS) in cold atoms. The experiment integrates a collinear 2DCS setup with a magneto-optical trap (MOT), in which cold rubidium (Rb) atoms are prepared at a temperature of approximately 200 µK and a number density of 1010 cm-3. With a sequence of femtosecond laser pulses, we first obtain one-dimensional second- and fourth-order nonlinear signals and then acquire both one-quantum and zero-quantum 2D spectra of cold Rb atoms. The capability of performing optical 2DCS in cold atoms is an important step toward optical 2DCS study of many-body physics in cold atoms and ultimately in atom arrays and trapped ions. Optical 2DCS in cold atoms/molecules can also be a new avenue to probe chemical reaction dynamics in cold molecules.
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Solowan HP, Malý P, Brixner T. Direct comparison of molecular-beam versus liquid-phase pump-probe and two-dimensional spectroscopy on the example of azulene. J Chem Phys 2022; 157:044201. [DOI: 10.1063/5.0088365] [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
Although azulene's anomalous fluorescence originating from S2 rather than from S1 is the textbook example for the violation of Kasha's rule, the understanding of the underlying processes is still a subject of investigation. Here, we use action-based coherent two-dimensional electronic spectroscopy (2DES) to measure a single Liouville-space response pathway from S0 via S1 to the S2 state of azulene. We directly compare this sequential excitation in liquid phase detecting S2 fluorescence and in a molecular beam detecting photoionized cations, using the S2 anomalous emission to our advantage. We complement the 2DES study by pump-probe measurements of S1 excitation dynamics, including vibrational relaxation and passage through a conical intersection. The direct comparison of liquid and gas phase allows us to assess the effect of the solvent and the interplay of intra- and inter-molecular energy relaxation.
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Affiliation(s)
| | - Pavel Malý
- Institute of Physical and Theoretical Chemistry, Julius-Maximilians-Universität Würzburg, Germany
| | - Tobias Brixner
- Institut fuer Physikalische und Theoretische Chemie, Julius-Maximilians-Universität Würzburg, Germany
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Bruder L, Wittenbecher L, Kolesnichenko PV, Zigmantas D. Generation and compression of 10-fs deep ultraviolet pulses at high repetition rate using standard optics. OPTICS EXPRESS 2021; 29:25593-25604. [PMID: 34614887 DOI: 10.1364/oe.425053] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/16/2021] [Indexed: 06/13/2023]
Abstract
The generation and characterization of ultrashort laser pulses in the deep ultraviolet spectral region is challenging, especially at high pulse repetition rates and low pulse energies. Here, we combine achromatic second harmonic generation and adaptive pulse compression for the efficient generation of sub-10 fs deep ultraviolet laser pulses at a laser repetition rate of 200 kHz. Furthermore, we simplify the pulse compression scheme and reach pulse durations of ≈10 fs without the use of adaptive optics. We demonstrate straight-forward tuning from 250 to 320 nm, broad pulse spectra of up to 63 nm width, excellent stability and a high robustness against misalignment. These features make the approach appealing for numerous spectroscopy and imaging applications.
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Pres S, Kontschak L, Hensen M, Brixner T. Coherent 2D electronic spectroscopy with complete characterization of excitation pulses during all scanning steps. OPTICS EXPRESS 2021; 29:4191-4209. [PMID: 33771004 DOI: 10.1364/oe.414452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/26/2020] [Indexed: 06/12/2023]
Abstract
Coherent two-dimensional (2D) electronic spectroscopy has become a standard tool in ultrafast science. Thus it is relevant to consider the accuracy of data considering both experimental imperfections and theoretical assumptions about idealized conditions. It is already known that chirped excitation pulses can affect 2D line shapes. In the present work, we demonstrate performance-efficient, automated characterization of the full electric field of each individual multipulse sequence employed during a 2D scanning procedure. Using Fourier-transform spectral interferometry, we analyze how the temporal intensity and phase profile varies from scanning step to scanning step and extract relevant pulse-sequence parameters. This takes into account both random and systematic variations during the scan that may be caused, for example, by femtosecond pulse-shaping artifacts. Using the characterized fields, we simulate and compare 2D spectra obtained with idealized and real shapes obtained from an LCD-based pulse shaper. Exemplarily, we consider fluorescence of a molecular dimer and multiphoton photoemission of a plasmonic nanoslit. The deviations from pulse-shaper artifacts in our specific case do not distort strongly the population-based multidimensional data. The characterization procedure is applicable to other pulses-shaping technologies or excitation geometries, including also pump-probe geometry with multipulse excitation and coherent detection, and allows for accurate consideration of realistic optical excitation fields at all inter-pulse time-delays.
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Sun K, Xie W, Chen L, Domcke W, Gelin MF. Multi-faceted spectroscopic mapping of ultrafast nonadiabatic dynamics near conical intersections: A computational study. J Chem Phys 2020; 153:174111. [DOI: 10.1063/5.0024148] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Kewei Sun
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Weiwei Xie
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Lipeng Chen
- Max Planck Institute for the Physics of Complex Systems, 38 Nöethnitzer Str., Dresden, Germany
| | - Wolfgang Domcke
- Department of Chemistry, Technische Universität München, D-85747 Garching, Germany
| | - Maxim F. Gelin
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
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Malý P, Mueller S, Lüttig J, Lambert C, Brixner T. Signatures of exciton dynamics and interaction in coherently and fluorescence-detected four- and six-wave-mixing two-dimensional electronic spectroscopy. J Chem Phys 2020; 153:144204. [PMID: 33086839 DOI: 10.1063/5.0022743] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Two-dimensional electronic spectroscopy (2DES) can be realized in increasing nonlinear orders of interaction with the electric field, bringing new information about single- and multi-particle properties and dynamics. Furthermore, signals can be detected both coherently (C-2DES) and by fluorescence (F-2DES), with fundamental and practical differences. We directly compare the simultaneous measurements of four- and six-wave mixing C-2DES and F-2DES on an excitonic heterodimer of squaraine molecules. Spectral features are described in increasing orders of nonlinearity by an explicit excitonic model. We demonstrate that the four-wave-mixing spectra are sensitive to one-exciton energies, their delocalization and dynamics, while the six-wave-mixing spectra include information on bi-exciton and higher excited states including the state energies, electronic coupling, and exciton-exciton annihilation. We focus on the possibility to extract the dynamics arising from exciton-exciton interaction directly from the six-wave-mixing spectra. To this end, in analogy to previously demonstrated fifth-order coherently detected exciton-exciton-interaction 2DES (EEI2D spectroscopy), we introduce a sixth-order fluorescence-detected EEI2D spectroscopy variant.
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Affiliation(s)
- Pavel Malý
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Stefan Mueller
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Julian Lüttig
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Christoph Lambert
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Tobias Brixner
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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