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Schlawin F. Two-photon absorption cross sections of pulsed entangled beams. J Chem Phys 2024; 160:144117. [PMID: 38619059 DOI: 10.1063/5.0196817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 03/24/2024] [Indexed: 04/16/2024] Open
Abstract
Entangled two-photon absorption (ETPA) could form the basis of nonlinear quantum spectroscopy at very low photon fluxes, since, at sufficiently low photon fluxes, ETPA scales linearly with the photon flux. When different pairs start to overlap temporally, accidental coincidences are thought to give rise to a "classical" quadratic scaling that dominates the signal at large photon fluxes and, thus, recovers a supposedly classical regime, where any quantum advantage is thought to be lost. Here, we scrutinize this assumption and demonstrate that quantum-enhanced absorption cross sections can persist even for very large photon numbers. To this end, we use a minimal model for quantum light, which can interpolate continuously between the entangled pair and a high-photon-flux limit, to analytically derive ETPA cross sections and the intensity crossover regime. We investigate the interplay between spectral and spatial degrees of freedom and how linewidth broadening of the sample impacts the experimentally achievable enhancement.
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Affiliation(s)
- Frank Schlawin
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany; University of Hamburg, Luruper Chaussee 149, Hamburg, Germany; and The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany
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Li Q, Orcutt K, Cook RL, Sabines-Chesterking J, Tong AL, Schlau-Cohen GS, Zhang X, Fleming GR, Whaley KB. Single-photon absorption and emission from a natural photosynthetic complex. Nature 2023:10.1038/s41586-023-06121-5. [PMID: 37316658 PMCID: PMC10338339 DOI: 10.1038/s41586-023-06121-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 04/24/2023] [Indexed: 06/16/2023]
Abstract
Photosynthesis is generally assumed to be initiated by a single photon1-3 from the Sun, which, as a weak light source, delivers at most a few tens of photons per nanometre squared per second within a chlorophyll absorption band1. Yet much experimental and theoretical work over the past 40 years has explored the events during photosynthesis subsequent to absorption of light from intense, ultrashort laser pulses2-15. Here, we use single photons to excite under ambient conditions the light-harvesting 2 (LH2) complex of the purple bacterium Rhodobacter sphaeroides, comprising B800 and B850 rings that contain 9 and 18 bacteriochlorophyll molecules, respectively. Excitation of the B800 ring leads to electronic energy transfer to the B850 ring in approximately 0.7 ps, followed by rapid B850-to-B850 energy transfer on an approximately 100-fs timescale and light emission at 850-875 nm (refs. 16-19). Using a heralded single-photon source20,21 along with coincidence counting, we establish time correlation functions for B800 excitation and B850 fluorescence emission and demonstrate that both events involve single photons. We also find that the probability distribution of the number of heralds per detected fluorescence photon supports the view that a single photon can upon absorption drive the subsequent energy transfer and fluorescence emission and hence, by extension, the primary charge separation of photosynthesis. An analytical stochastic model and a Monte Carlo numerical model capture the data, further confirming that absorption of single photons is correlated with emission of single photons in a natural light-harvesting complex.
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Affiliation(s)
- Quanwei Li
- Department of Chemistry, University of California, Berkeley, CA, USA
- Kavli Energy Nanoscience Institute at Berkeley, Berkeley, CA, USA
| | - Kaydren Orcutt
- Department of Chemistry, University of California, Berkeley, CA, USA
- Kavli Energy Nanoscience Institute at Berkeley, Berkeley, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Robert L Cook
- Department of Chemistry, University of California, Berkeley, CA, USA
- Kavli Energy Nanoscience Institute at Berkeley, Berkeley, CA, USA
| | - Javier Sabines-Chesterking
- Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, MD, USA
| | - Ashley L Tong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Xiang Zhang
- Kavli Energy Nanoscience Institute at Berkeley, Berkeley, CA, USA
- Nanoscale Science and Engineering Center, University of California, Berkeley, CA, USA
| | - Graham R Fleming
- Department of Chemistry, University of California, Berkeley, CA, USA.
- Kavli Energy Nanoscience Institute at Berkeley, Berkeley, CA, USA.
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - K Birgitta Whaley
- Department of Chemistry, University of California, Berkeley, CA, USA.
- Kavli Energy Nanoscience Institute at Berkeley, Berkeley, CA, USA.
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Zhang Y, Huo N, Cui L, Guo X, Li X, Ou ZY. Temporal coherence in an unbalanced SU(1,1) interferometer. OPTICS LETTERS 2023; 48:127-130. [PMID: 36563385 DOI: 10.1364/ol.470115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/31/2022] [Indexed: 06/17/2023]
Abstract
In classical coherence theory, coherence time is typically related to the bandwidth of the optical field. Narrowing the bandwidth by optical filtering will result in the lengthening of the coherence time. In the case of a delayed pulse photon interference, this will lead to pulse overlap and recovery of interference, which is otherwise absent due to time delay. However, this is changed for entangled optical fields. In this Letter, we investigate how the temporal coherence of the fields in a pulse-pumped SU(1,1) interferometer changes with the bandwidth of optical filtering. We find that the effect of optical filtering is not similar to the classical coherence theory in the presence of quantum entanglement. A full quantum theory is presented and can explain the phenomena well.
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Ren H, Li H, Zhang Q, Liang L, Guo W, Huang F, Luo Y, Jiang J. A machine learning vibrational spectroscopy protocol for spectrum prediction and spectrum-based structure recognition. FUNDAMENTAL RESEARCH 2021. [DOI: 10.1016/j.fmre.2021.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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Carnio EG, Buchleitner A, Schlawin F. Optimization of selective two-photon absorption in cavity polaritons. J Chem Phys 2021; 154:214114. [PMID: 34240974 DOI: 10.1063/5.0049863] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We investigate optimal states of photon pairs to excite a target transition in a multilevel quantum system. With the help of coherent control theory for two-photon absorption with quantum light, we infer the maximal population achievable by optimal entangled vs separable states of light. Interference between excitation pathways as well as the presence of nearby states may hamper the selective excitation of a particular target state, but we show that quantum correlations can help to overcome this problem and enhance the achievable "selectivity" between two energy levels, i.e., the relative difference in population transferred into each of them. We find that the added value of optimal entangled states of light increases with broadening linewidths of the target states.
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Affiliation(s)
- Edoardo G Carnio
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, D-79104 Freiburg, Germany
| | - Andreas Buchleitner
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, D-79104 Freiburg, Germany
| | - Frank Schlawin
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany
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Ishizaki A, Fleming GR. Insights into Photosynthetic Energy Transfer Gained from Free-Energy Structure: Coherent Transport, Incoherent Hopping, and Vibrational Assistance Revisited. J Phys Chem B 2021; 125:3286-3295. [PMID: 33724833 DOI: 10.1021/acs.jpcb.0c09847] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Giant strides in ultrashort laser pulse technology have enabled real-time observation of dynamical processes in complex molecular systems. Specifically, the discovery of oscillatory transients in the two-dimensional electronic spectra of photosynthetic systems stimulated a number of theoretical investigations exploring the possible physical mechanisms of the remarkable quantum efficiency of light harvesting processes. In this work, we revisit the elementary aspects of environment-induced fluctuations in the involved electronic energies and present a simple way to understand energy flow with the intuitive picture of relaxation in a funnel-type free-energy landscape. The presented free-energy description of energy transfer reveals that typical photosynthetic systems operate in an almost barrierless regime. The approach also provides insights into the distinction between coherent and incoherent energy transfer and the criteria by which the necessity of the vibrational assistance is considered.
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Affiliation(s)
- Akihito Ishizaki
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585, Japan.,School of Physical Sciences, Graduate University for Advanced Studies, Okazaki 444-8585, Japan
| | - Graham R Fleming
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,Kavli Energy NanoSciences Institute at Berkeley, Berkeley, California 94720, United States
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Lüders C, Aßmann M. Distinguishing intrinsic photon correlations from external noise with frequency-resolved homodyne detection. Sci Rep 2020; 10:22411. [PMID: 33376250 PMCID: PMC7772345 DOI: 10.1038/s41598-020-79686-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 12/11/2020] [Indexed: 11/09/2022] Open
Abstract
In this work, we apply homodyne detection to investigate the frequency-resolved photon statistics of a cw light field emitted by a driven-dissipative semiconductor system in real time. We demonstrate that studying the frequency dependence of the photon number noise allows us to distinguish intrinsic noise properties of the emitter from external noise sources such as mechanical noise while maintaining a sub-picosecond temporal resolution. We further show that performing postselection on the recorded data opens up the possibility to study rare events in the dynamics of the emitter. By doing so, we demonstrate that in rare instances, additional external noise may actually result in reduced photon number noise in the emission.
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Affiliation(s)
- Carolin Lüders
- Experimentelle Physik 2, Technische Universität Dortmund, 44221, Dortmund, Germany
| | - Marc Aßmann
- Experimentelle Physik 2, Technische Universität Dortmund, 44221, Dortmund, Germany.
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