Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1909.11205 · Physical Review A

Photon-matter quantum correlations in spontaneous Raman scattering

Kai Shinbrough, Yanting Teng, Bin Fang, Virginia O. Lorenz, Offir Cohen

Published Jan 10, 2020• 4 citations
arXivHTMLPDF

Abstract

We develop a Hamiltonian formalism to study energy and position (momentum) correlations between a single Stokes photon and a single material excitation that are created as a pair in the spontaneous Raman scattering process. Our approach allows for intuitive separation of the effects of spectral linewidth, chromatic dispersion, and collection angle on these correlations, and we compare the predictions of the model to experiment. These results have important implications for the use of Raman scattering in quantum protocols that rely on spectrally unentangled photons and collective excitations.

DOI
10.1103/physreva.101.013415

Related papers

Raman Scattering Beyond the Master Equation: Photon-Matter Correlations and Statistics

Kai Shinbrough, Yanting Teng, Bin Fang +2 more

We present 1D and 3D models that take into account Stokes-photon–excitation pair correlations in Raman scattering, revealing nontrivial dependence of the photon statistics on linewidth, dispersion and collection angle.

Conference on Lasers and Electro-Optics•Jan 1, 2019•0 citations

Raman Scattering Beyond the Master Equation: Photon-Matter Correlations and Statistics

Kai Shinbrough, Yanting Teng, Bin Fang +2 more

We present 1D and 3D models that take into account Stokes-photon-excitation pair correlations in Raman scattering, revealing nontrivial dependence of the photon statistics on linewidth, dispersion and collection angle. © 2019 The Author(s)

Conference on Lasers and Electro-Optics•Jan 1, 2019•0 citations

Measurement-induced collective vibrational quantum coherence under spontaneous Raman scattering in a liquid

Valeria Vento, Santiago Tarrago Velez, A. Pogrebna +1 more

Spontaneous vibrational Raman scattering is a ubiquitous form of light-matter interaction whose description necessitates quantization of the electromagnetic field. It is usually considered as an incoherent process because the scattered field lacks any predictable phase relationship with the incoming field. When probing an ensemble of molecules, the question therefore arises: What quantum state should be used to describe the molecular ensemble following spontaneous Stokes scattering? We experimentally address this question by measuring time-resolved Stokes-anti-Stokes two-photon coincidences on a molecular liquid consisting of several sub-ensembles with slightly different vibrational frequencies. When spontaneously scattered Stokes photons and subsequent anti-Stokes photons are detected into a single spatiotemporal mode, the observed dynamics is inconsistent with a statistical mixture of individually excited molecules. Instead, we show that the data are reproduced if Stokes-anti-Stokes correlations are mediated by a collective vibrational quantum, i.e. a coherent superposition of all molecules interacting with light. Our results demonstrate that the degree of coherence in the vibrational state of the liquid is not an intrinsic property of the material system, but rather depends on the optical excitation and detection geometry.

arXiv:2105.00213•Nature Communications•May 17, 2023•15 citations

Quantum applications of Raman-mediated photon-pair generation

Kathleen Oolman

Controllable generation of photon pairs is essential for the utilization of quantum pair states for quantum applications such as quantum communication, quantum cryptography, teleportation, and linear optics quantum computing. Raman scattering is one of the most fundamental light-matter interactions and can be used to generate photon pairs. Using the spontaneous Stokes Raman interaction, a photon from a strong pump laser pulse is annihilated, and a Stokes photon and Raman-mediated collective excitation are created. This excitation can then be read out deterministically as an anti-Stokes photon with the application of a second laser pulse within the excitation lifetime, creating a photon pair. The heralding capability of the Stokes photon and lifetime of the excitation makes this source quasi-deterministic, where the anti-Stokes photon can be created at a later time than the Stokes. This gives additional advantages and uses over traditional photon-pair sources using nonlinear interactions of light in a transparent medium, which generate the pair of photons simultaneously. In this thesis, we study the correlations of photon pairs generated via spontaneous Raman interactions and demonstrate how these interactions can be used for quantum applications. First, we develop a model to study the spectral correlations between the Raman generated Stokes and anti-Stokes photons. This model is used to calculate the spectral single-photon purity of the photons in a generic material system ignoring the effects of material dispersion. We calculate how various parameters effect the purity including pump spectral bandwidth, excitation linewidth, and time delay between pump pulses. We then introduced an experimental realization of a Raman-mediated photon-pair source in an integrated quantum photonic circuit platform. Interstitial N2 molecules inherently trapped in silicon nitride thin films during the deposition process possess a sharp Raman mission corresponding to the vibrational mode of the molecules, which can be used as a Raman-mediated photon-pair source. We present evidence of N2 defects in silicon nitride thin films and estimate the defect density and excitation lifetime. By patterning the films into waveguide structures, the photon-matter interaction is enhanced. We perform finite-element simulation of light propagation in our fabricated waveguides and use the results to examine effects from the waveguide on ultrafast optical pulses and phase-matching requirements for efficient photon-pair generation. We then present experimental progress towards detecting Stokes and anti-Stokes photon-pair generation from N2 defects in silicon nitride waveguides. We show results from degenerate and non-degenerate wavelength optical pump pulses. We discuss limitations of the experimental methods and study in detail the sources of noise arising from the silicon nitride waveguide, and conclude by discussing future extensions on the results presented here.

•Oct 17, 2024•0 citations

Collective Vibrational Quantum Coherence in a Molecular Liquid under Spontaneous Raman Scattering

Santiago Tarrago Velez, A. Pogrebna, Christophe Galland

Stimulated Raman scattering is conventionally employed to probe vibrational dynamics by inducing a coherent oscillation within a molecular ensemble. In contrast, spontaneous Raman scattering is considered as an incoherent process because the scattered field lacks any predictable phase relationship with the incoming laser pulse. It raises questions about the nature of the quantum state of a molecular ensemble following spontaneous Stokes scattering: should it be described as a statistical mixture of vibrationally excited molecules, where collective coherence is absent? Here, we measure time-resolved Stokes--anti-Stokes two-photon coincidences on a molecular liquid and find that a coherent superposition of two collective vibrational modes from two isotopic sub-ensembles is generated under spontaneous Raman scattering. Our results confirm that a spatially extended vibrational coherence emerges when a single collective excitation is spontaneously scattered and detected in a single spatiotemporal mode.

•May 1, 2021•1 citation

Quantum correlations in the Stokes and anti-Stokes Raman scattering: the photonic counterparts of Cooper pairs

Filomeno Soares de Aguiar Júnior

The correlated Raman scattering, referred to here as the SaS process, occurs with the annihilation, within a material, of two photons of an excitation laser and the creation of a quantum correlated Stokes (S) and anti-Soktes (aS) photon pair where the phonon created in the S process is annihilated in the aS scattering. We found that, in addition to real SaS process where the energy exchange coincides with the energy of a vibrational state of the material, there is also the virtual SaS process, whose the exchange of energy and momentum between the photons of the laser, generating the S-aS photon pair, is mediated by a virtual vibrational excitation, setting up a photon-photon interaction similar to the electron-electron attraction responsible for the creation of Cooper pairs of the BCS theory of superconductivity. We observed the SaS process in transparent media in general, by measuring non-classical values of the normalized second-order cross-correlation function of the Stokes and anti-Stokes fields, 2(0). In diamond, we characterize the intensity of the virtual SaS scattering ( ) as a function of the virtual phonon energy, proving that the SaS process occurs only when the photon-photon interaction is attractive, as in the BCS theory for the Cooper pairs. We show that photons S and aS from the SaS process are scattered predominantly in the same polarization as the excitation laser of the sample and, with this, we implemented the pump-probe technique to study the lifetime of the real phonon (obtained in the diamond order 2.8 ps ) and the lifetime of the virtual excitation, which proved to be inferior to the temporal resolution of the measurement’s, characterizing one of the main differences between the two processes. We also observed that, due to the relations of energy and momentum conservation, have the same spatial intensity profile of the non-interacting laser that crosses the sample, different from the behavior observed for uncorrelated Raman scattering which spreads photons in all directions. We observed that the efficiency of the SaS scattering is proportional to the Raman scattering cross-section when we compare the process in different hydrocarbons and we generalize the observations made in the diamond to the sample of liquid decane. In water, the values of 2(0), predicted by the theoretical description of the process, corroborate the experimental data, validating the BCS theory for virtual SaS scattering, setting the pair of Stokes and anti-Stokes photons as counterparts of the Cooper pairs.

•Nov 25, 2020•0 citations
We develop a Hamiltonian formalism to study energy and position (momentum) correlations between a single Stokes photon and a single material excitation that are created as a pair in the spontaneous Raman scattering process. Our approach allows for intuitive separation of the effects of spectral linewidth, chromatic dispersion, and collection angle on these correlations, and we compare the predictions of the model to experiment. These results have important implications for the use of Raman scattering in quantum protocols that rely on spectrally unentangled photons and collective excitations.
Spontaneous vibrational Raman scattering is a ubiquitous form of light-matter interaction whose description necessitates quantization of the electromagnetic field. It is usually considered as an incoherent process because the scattered field lacks any predictable phase relationship with the incoming field. When probing an ensemble of molecules, the question therefore arises: What quantum state should be used to describe the molecular ensemble following spontaneous Stokes scattering? We experimentally address this question by measuring time-resolved Stokes-anti-Stokes two-photon coincidences on a molecular liquid consisting of several sub-ensembles with slightly different vibrational frequencies. When spontaneously scattered Stokes photons and subsequent anti-Stokes photons are detected into a single spatiotemporal mode, the observed dynamics is inconsistent with a statistical mixture of individually excited molecules. Instead, we show that the data are reproduced if Stokes-anti-Stokes correlations are mediated by a collective vibrational quantum, i.e. a coherent superposition of all molecules interacting with light. Our results demonstrate that the degree of coherence in the vibrational state of the liquid is not an intrinsic property of the material system, but rather depends on the optical excitation and detection geometry.
Controllable generation of photon pairs is essential for the utilization of quantum pair states for quantum applications such as quantum communication, quantum cryptography, teleportation, and linear optics quantum computing. Raman scattering is one of the most fundamental light-matter interactions and can be used to generate photon pairs. Using the spontaneous Stokes Raman interaction, a photon from a strong pump laser pulse is annihilated, and a Stokes photon and Raman-mediated collective excitation are created. This excitation can then be read out deterministically as an anti-Stokes photon with the application of a second laser pulse within the excitation lifetime, creating a photon pair. The heralding capability of the Stokes photon and lifetime of the excitation makes this source quasi-deterministic, where the anti-Stokes photon can be created at a later time than the Stokes. This gives additional advantages and uses over traditional photon-pair sources using nonlinear interactions of light in a transparent medium, which generate the pair of photons simultaneously. In this thesis, we study the correlations of photon pairs generated via spontaneous Raman interactions and demonstrate how these interactions can be used for quantum applications. First, we develop a model to study the spectral correlations between the Raman generated Stokes and anti-Stokes photons. This model is used to calculate the spectral single-photon purity of the photons in a generic material system ignoring the effects of material dispersion. We calculate how various parameters effect the purity including pump spectral bandwidth, excitation linewidth, and time delay between pump pulses. We then introduced an experimental realization of a Raman-mediated photon-pair source in an integrated quantum photonic circuit platform. Interstitial N2 molecules inherently trapped in silicon nitride thin films during the deposition process possess a sharp Raman mission corresponding to the vibrational mode of the molecules, which can be used as a Raman-mediated photon-pair source. We present evidence of N2 defects in silicon nitride thin films and estimate the defect density and excitation lifetime. By patterning the films into waveguide structures, the photon-matter interaction is enhanced. We perform finite-element simulation of light propagation in our fabricated waveguides and use the results to examine effects from the waveguide on ultrafast optical pulses and phase-matching requirements for efficient photon-pair generation. We then present experimental progress towards detecting Stokes and anti-Stokes photon-pair generation from N2 defects in silicon nitride waveguides. We show results from degenerate and non-degenerate wavelength optical pump pulses. We discuss limitations of the experimental methods and study in detail the sources of noise arising from the silicon nitride waveguide, and conclude by discussing future extensions on the results presented here.
Stimulated Raman scattering is conventionally employed to probe vibrational dynamics by inducing a coherent oscillation within a molecular ensemble. In contrast, spontaneous Raman scattering is considered as an incoherent process because the scattered field lacks any predictable phase relationship with the incoming laser pulse. It raises questions about the nature of the quantum state of a molecular ensemble following spontaneous Stokes scattering: should it be described as a statistical mixture of vibrationally excited molecules, where collective coherence is absent? Here, we measure time-resolved Stokes--anti-Stokes two-photon coincidences on a molecular liquid and find that a coherent superposition of two collective vibrational modes from two isotopic sub-ensembles is generated under spontaneous Raman scattering. Our results confirm that a spatially extended vibrational coherence emerges when a single collective excitation is spontaneously scattered and detected in a single spatiotemporal mode.
The correlated Raman scattering, referred to here as the SaS process, occurs with the annihilation, within a material, of two photons of an excitation laser and the creation of a quantum correlated Stokes (S) and anti-Soktes (aS) photon pair where the phonon created in the S process is annihilated in the aS scattering. We found that, in addition to real SaS process where the energy exchange coincides with the energy of a vibrational state of the material, there is also the virtual SaS process, whose the exchange of energy and momentum between the photons of the laser, generating the S-aS photon pair, is mediated by a virtual vibrational excitation, setting up a photon-photon interaction similar to the electron-electron attraction responsible for the creation of Cooper pairs of the BCS theory of superconductivity. We observed the SaS process in transparent media in general, by measuring non-classical values of the normalized second-order cross-correlation function of the Stokes and anti-Stokes fields, 2(0). In diamond, we characterize the intensity of the virtual SaS scattering ( ) as a function of the virtual phonon energy, proving that the SaS process occurs only when the photon-photon interaction is attractive, as in the BCS theory for the Cooper pairs. We show that photons S and aS from the SaS process are scattered predominantly in the same polarization as the excitation laser of the sample and, with this, we implemented the pump-probe technique to study the lifetime of the real phonon (obtained in the diamond order 2.8 ps ) and the lifetime of the virtual excitation, which proved to be inferior to the temporal resolution of the measurement’s, characterizing one of the main differences between the two processes. We also observed that, due to the relations of energy and momentum conservation, have the same spatial intensity profile of the non-interacting laser that crosses the sample, different from the behavior observed for uncorrelated Raman scattering which spreads photons in all directions. We observed that the efficiency of the SaS scattering is proportional to the Raman scattering cross-section when we compare the process in different hydrocarbons and we generalize the observations made in the diamond to the sample of liquid decane. In water, the values of 2(0), predicted by the theoretical description of the process, corroborate the experimental data, validating the BCS theory for virtual SaS scattering, setting the pair of Stokes and anti-Stokes photons as counterparts of the Cooper pairs.