---
_id: '14466'
abstract:
- lang: eng
  text: The first long-lived turbulent structures observable in planar shear flows
    take the form of localized stripes, inclined with respect to the mean flow direction.
    The dynamics of these stripes is central to transition, and recent studies proposed
    an analogy to directed percolation where the stripes’ proliferation is ultimately
    responsible for the turbulence becoming sustained. In the present study we focus
    on the internal stripe dynamics as well as on the eventual stripe expansion, and
    we compare the underlying mechanisms in pressure- and shear-driven planar flows,
    respectively, plane-Poiseuille and plane-Couette flow. Despite the similarities
    of the overall laminar–turbulence patterns, the stripe proliferation processes
    in the two cases are fundamentally different. Starting from the growth and sustenance
    of individual stripes, we find that in plane-Couette flow new streaks are created
    stochastically throughout the stripe whereas in plane-Poiseuille flow streak creation
    is deterministic and occurs locally at the downstream tip. Because of the up/downstream
    symmetry, Couette stripes, in contrast to Poiseuille stripes, have two weak and
    two strong laminar turbulent interfaces. These differences in symmetry as well
    as in internal growth give rise to two fundamentally different stripe splitting
    mechanisms. In plane-Poiseuille flow splitting is connected to the elongational
    growth of the original stripe, and it results from a break-off/shedding of the
    stripe's tail. In plane-Couette flow splitting follows from a broadening of the
    original stripe and a division along the stripe into two slimmer stripes.
acknowledgement: E.M. acknowledges funding from the ISTplus fellowship programme.
  G.Y. and B.H. acknowledge a grant from the Simons Foundation (662960, BH).
article_number: A21
article_processing_charge: Yes (via OA deal)
article_type: original
arxiv: 1
author:
- first_name: Elena
  full_name: Marensi, Elena
  id: 0BE7553A-1004-11EA-B805-18983DDC885E
  last_name: Marensi
  orcid: 0000-0001-7173-4923
- first_name: Gökhan
  full_name: Yalniz, Gökhan
  id: 66E74FA2-D8BF-11E9-8249-8DE2E5697425
  last_name: Yalniz
  orcid: 0000-0002-8490-9312
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
citation:
  ama: Marensi E, Yalniz G, Hof B. Dynamics and proliferation of turbulent stripes
    in plane-Poiseuille and plane-Couette flows. <i>Journal of Fluid Mechanics</i>.
    2023;974. doi:<a href="https://doi.org/10.1017/jfm.2023.780">10.1017/jfm.2023.780</a>
  apa: Marensi, E., Yalniz, G., &#38; Hof, B. (2023). Dynamics and proliferation of
    turbulent stripes in plane-Poiseuille and plane-Couette flows. <i>Journal of Fluid
    Mechanics</i>. Cambridge University Press. <a href="https://doi.org/10.1017/jfm.2023.780">https://doi.org/10.1017/jfm.2023.780</a>
  chicago: Marensi, Elena, Gökhan Yalniz, and Björn Hof. “Dynamics and Proliferation
    of Turbulent Stripes in Plane-Poiseuille and Plane-Couette Flows.” <i>Journal
    of Fluid Mechanics</i>. Cambridge University Press, 2023. <a href="https://doi.org/10.1017/jfm.2023.780">https://doi.org/10.1017/jfm.2023.780</a>.
  ieee: E. Marensi, G. Yalniz, and B. Hof, “Dynamics and proliferation of turbulent
    stripes in plane-Poiseuille and plane-Couette flows,” <i>Journal of Fluid Mechanics</i>,
    vol. 974. Cambridge University Press, 2023.
  ista: Marensi E, Yalniz G, Hof B. 2023. Dynamics and proliferation of turbulent
    stripes in plane-Poiseuille and plane-Couette flows. Journal of Fluid Mechanics.
    974, A21.
  mla: Marensi, Elena, et al. “Dynamics and Proliferation of Turbulent Stripes in
    Plane-Poiseuille and Plane-Couette Flows.” <i>Journal of Fluid Mechanics</i>,
    vol. 974, A21, Cambridge University Press, 2023, doi:<a href="https://doi.org/10.1017/jfm.2023.780">10.1017/jfm.2023.780</a>.
  short: E. Marensi, G. Yalniz, B. Hof, Journal of Fluid Mechanics 974 (2023).
date_created: 2023-10-30T09:32:28Z
date_published: 2023-11-10T00:00:00Z
date_updated: 2024-02-15T09:06:23Z
day: '10'
ddc:
- '530'
department:
- _id: GradSch
- _id: BjHo
doi: 10.1017/jfm.2023.780
external_id:
  arxiv:
  - '2212.12406'
  isi:
  - '001088363700001'
file:
- access_level: open_access
  checksum: 17c64c1fb0d5f73252364bf98b0b9e1a
  content_type: application/pdf
  creator: dernst
  date_created: 2024-02-15T09:05:21Z
  date_updated: 2024-02-15T09:05:21Z
  file_id: '14996'
  file_name: 2023_JourFluidMechanics_Marensi.pdf
  file_size: 2804641
  relation: main_file
  success: 1
file_date_updated: 2024-02-15T09:05:21Z
has_accepted_license: '1'
intvolume: '       974'
isi: 1
keyword:
- turbulence
- transition to turbulence
- patterns
language:
- iso: eng
month: '11'
oa: 1
oa_version: Published Version
project:
- _id: 238598C6-32DE-11EA-91FC-C7463DDC885E
  grant_number: '662960'
  name: 'Revisiting the Turbulence Problem Using Statistical Mechanics: Experimental
    Studies on Transitional and Turbulent Flows'
publication: Journal of Fluid Mechanics
publication_identifier:
  eissn:
  - 1469-7645
  issn:
  - 0022-1120
publication_status: published
publisher: Cambridge University Press
quality_controlled: '1'
status: public
title: Dynamics and proliferation of turbulent stripes in plane-Poiseuille and plane-Couette
  flows
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 974
year: '2023'
...
---
_id: '12105'
abstract:
- lang: eng
  text: Data-driven dimensionality reduction methods such as proper orthogonal decomposition
    and dynamic mode decomposition have proven to be useful for exploring complex
    phenomena within fluid dynamics and beyond. A well-known challenge for these techniques
    is posed by the continuous symmetries, e.g. translations and rotations, of the
    system under consideration, as drifts in the data dominate the modal expansions
    without providing an insight into the dynamics of the problem. In the present
    study, we address this issue for fluid flows in rectangular channels by formulating
    a continuous symmetry reduction method that eliminates the translations in the
    streamwise and spanwise directions simultaneously. We demonstrate our method by
    computing the symmetry-reduced dynamic mode decomposition (SRDMD) of sliding windows
    of data obtained from the transitional plane-Couette and turbulent plane-Poiseuille
    flow simulations. In the former setting, SRDMD captures the dynamics in the vicinity
    of the invariant solutions with translation symmetries, i.e. travelling waves
    and relative periodic orbits, whereas in the latter, our calculations reveal episodes
    of turbulent time evolution that can be approximated by a low-dimensional linear
    expansion.
acknowledgement: "E.M. acknowledges funding from the ISTplus fellowship programme.
  G.Y. and B.H. acknowledge\r\na grant from the Simons Foundation (662960, BH)."
article_number: A10
article_processing_charge: Yes (via OA deal)
article_type: original
arxiv: 1
author:
- first_name: Elena
  full_name: Marensi, Elena
  id: 0BE7553A-1004-11EA-B805-18983DDC885E
  last_name: Marensi
- first_name: Gökhan
  full_name: Yalniz, Gökhan
  id: 66E74FA2-D8BF-11E9-8249-8DE2E5697425
  last_name: Yalniz
  orcid: 0000-0002-8490-9312
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
- first_name: Nazmi B
  full_name: Budanur, Nazmi B
  id: 3EA1010E-F248-11E8-B48F-1D18A9856A87
  last_name: Budanur
  orcid: 0000-0003-0423-5010
citation:
  ama: Marensi E, Yalniz G, Hof B, Budanur NB. Symmetry-reduced dynamic mode decomposition
    of near-wall turbulence. <i>Journal of Fluid Mechanics</i>. 2023;954. doi:<a href="https://doi.org/10.1017/jfm.2022.1001">10.1017/jfm.2022.1001</a>
  apa: Marensi, E., Yalniz, G., Hof, B., &#38; Budanur, N. B. (2023). Symmetry-reduced
    dynamic mode decomposition of near-wall turbulence. <i>Journal of Fluid Mechanics</i>.
    Cambridge University Press. <a href="https://doi.org/10.1017/jfm.2022.1001">https://doi.org/10.1017/jfm.2022.1001</a>
  chicago: Marensi, Elena, Gökhan Yalniz, Björn Hof, and Nazmi B Budanur. “Symmetry-Reduced
    Dynamic Mode Decomposition of near-Wall Turbulence.” <i>Journal of Fluid Mechanics</i>.
    Cambridge University Press, 2023. <a href="https://doi.org/10.1017/jfm.2022.1001">https://doi.org/10.1017/jfm.2022.1001</a>.
  ieee: E. Marensi, G. Yalniz, B. Hof, and N. B. Budanur, “Symmetry-reduced dynamic
    mode decomposition of near-wall turbulence,” <i>Journal of Fluid Mechanics</i>,
    vol. 954. Cambridge University Press, 2023.
  ista: Marensi E, Yalniz G, Hof B, Budanur NB. 2023. Symmetry-reduced dynamic mode
    decomposition of near-wall turbulence. Journal of Fluid Mechanics. 954, A10.
  mla: Marensi, Elena, et al. “Symmetry-Reduced Dynamic Mode Decomposition of near-Wall
    Turbulence.” <i>Journal of Fluid Mechanics</i>, vol. 954, A10, Cambridge University
    Press, 2023, doi:<a href="https://doi.org/10.1017/jfm.2022.1001">10.1017/jfm.2022.1001</a>.
  short: E. Marensi, G. Yalniz, B. Hof, N.B. Budanur, Journal of Fluid Mechanics 954
    (2023).
date_created: 2023-01-08T23:00:53Z
date_published: 2023-01-10T00:00:00Z
date_updated: 2023-08-01T12:53:23Z
day: '10'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1017/jfm.2022.1001
external_id:
  arxiv:
  - '2101.07516'
  isi:
  - '000903336600001'
file:
- access_level: open_access
  checksum: 9224f987caefe5dd85a70814d3cce65c
  content_type: application/pdf
  creator: dernst
  date_created: 2023-02-02T12:34:54Z
  date_updated: 2023-02-02T12:34:54Z
  file_id: '12489'
  file_name: 2023_JourFluidMechanics_Marensi.pdf
  file_size: 1931647
  relation: main_file
  success: 1
file_date_updated: 2023-02-02T12:34:54Z
has_accepted_license: '1'
intvolume: '       954'
isi: 1
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
project:
- _id: 238598C6-32DE-11EA-91FC-C7463DDC885E
  grant_number: '662960'
  name: 'Revisiting the Turbulence Problem Using Statistical Mechanics: Experimental
    Studies on Transitional and Turbulent Flows'
publication: Journal of Fluid Mechanics
publication_identifier:
  eissn:
  - 1469-7645
  issn:
  - 0022-1120
publication_status: published
publisher: Cambridge University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: Symmetry-reduced dynamic mode decomposition of near-wall turbulence
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 954
year: '2023'
...
---
_id: '10820'
abstract:
- lang: eng
  text: Streaky structures in the boundary layers are often generated by surface roughness
    elements and/or free-stream turbulence, and are known to have significant effects
    on boundary-layer instability. In this paper, we investigate the impact of two
    forms of streaks on the instability of supersonic boundary layers. The first concerns
    the streaks generated by an array of spanwise periodic and streamwise elongated
    surface roughness elements, and our interest is how these streaks influence the
    lower-branch viscous first modes, whose characteristic wavelength and frequency
    are on the classical triple-deck scales. By adapting the triple-deck theory in
    the incompressible regime to the supersonic one, we first derived a simplified
    system which allows for efficient calculation of the streaks. The asymptotic analysis
    simplifies a bi-global eigenvalue problem to a one-dimensional problem in the
    spanwise direction, showing that the instability is controlled at leading order
    solely by the spanwise-dependent wall shear. In the fundamental configuration,
    the streaks stabilize first modes at low frequencies but destabilize the high-frequency
    ones. In the subharmonic configuration, the streaks generally destabilize the
    first mode across the entire frequency band. Importantly, the spanwise even modes
    are of radiating nature, i.e. they emit acoustic waves spontaneously to the far
    field. Streaks of the second form are generated by low-frequency vortical disturbances
    representing free-stream turbulence. They alter the flow in the entire layer and
    their effects on instability are investigated by solving the inviscid bi-global
    eigenvalue problem. Different from the incompressible case, a multitude of compressible
    instability modes exists, of which the dominant mode is an inviscid instability
    associated with the spanwise shear. In addition, there exists a separate branch
    of instability modes that have smaller growth rates but are spontaneously radiating.
acknowledgement: The work is supported by the National Key Research and Development
  Program of China (No. 2016YFA0401200), the National Natural Science Foundation of
  China (Grant Nos. 91952202 and 11402167).
article_processing_charge: No
author:
- first_name: Jianxin
  full_name: Liu, Jianxin
  last_name: Liu
- first_name: Elena
  full_name: Marensi, Elena
  id: 0BE7553A-1004-11EA-B805-18983DDC885E
  last_name: Marensi
- first_name: Xuesong
  full_name: Wu, Xuesong
  last_name: Wu
citation:
  ama: 'Liu J, Marensi E, Wu X. Effects of streaky structures on the instability of
    supersonic boundary layers. In: Sherwin S, Schmid P, Wu X, eds. <i>IUTAM Laminar-Turbulent
    Transition</i>. Vol 38. 1st ed. IUTAM Bookseries. Cham: Springer Nature; 2022:587-598.
    doi:<a href="https://doi.org/10.1007/978-3-030-67902-6_51">10.1007/978-3-030-67902-6_51</a>'
  apa: 'Liu, J., Marensi, E., &#38; Wu, X. (2022). Effects of streaky structures on
    the instability of supersonic boundary layers. In S. Sherwin, P. Schmid, &#38;
    X. Wu (Eds.), <i>IUTAM Laminar-Turbulent Transition</i> (1st ed., Vol. 38, pp.
    587–598). Cham: Springer Nature. <a href="https://doi.org/10.1007/978-3-030-67902-6_51">https://doi.org/10.1007/978-3-030-67902-6_51</a>'
  chicago: 'Liu, Jianxin, Elena Marensi, and Xuesong Wu. “Effects of Streaky Structures
    on the Instability of Supersonic Boundary Layers.” In <i>IUTAM Laminar-Turbulent
    Transition</i>, edited by Spencer Sherwin, Peter Schmid, and Xuesong Wu, 1st ed.,
    38:587–98. IUTAM Bookseries. Cham: Springer Nature, 2022. <a href="https://doi.org/10.1007/978-3-030-67902-6_51">https://doi.org/10.1007/978-3-030-67902-6_51</a>.'
  ieee: 'J. Liu, E. Marensi, and X. Wu, “Effects of streaky structures on the instability
    of supersonic boundary layers,” in <i>IUTAM Laminar-Turbulent Transition</i>,
    1st ed., vol. 38, S. Sherwin, P. Schmid, and X. Wu, Eds. Cham: Springer Nature,
    2022, pp. 587–598.'
  ista: 'Liu J, Marensi E, Wu X. 2022.Effects of streaky structures on the instability
    of supersonic boundary layers. In: IUTAM Laminar-Turbulent Transition. vol. 38,
    587–598.'
  mla: Liu, Jianxin, et al. “Effects of Streaky Structures on the Instability of Supersonic
    Boundary Layers.” <i>IUTAM Laminar-Turbulent Transition</i>, edited by Spencer
    Sherwin et al., 1st ed., vol. 38, Springer Nature, 2022, pp. 587–98, doi:<a href="https://doi.org/10.1007/978-3-030-67902-6_51">10.1007/978-3-030-67902-6_51</a>.
  short: J. Liu, E. Marensi, X. Wu, in:, S. Sherwin, P. Schmid, X. Wu (Eds.), IUTAM
    Laminar-Turbulent Transition, 1st ed., Springer Nature, Cham, 2022, pp. 587–598.
conference:
  end_date: 2019-09-06
  location: London, United Kingdom
  name: IUTAM Symposium
  start_date: 2019-09-02
date_created: 2022-03-04T09:14:34Z
date_published: 2022-01-01T00:00:00Z
date_updated: 2023-08-03T12:54:59Z
day: '01'
department:
- _id: BjHo
doi: 10.1007/978-3-030-67902-6_51
edition: '1'
editor:
- first_name: Spencer
  full_name: Sherwin, Spencer
  last_name: Sherwin
- first_name: Peter
  full_name: Schmid, Peter
  last_name: Schmid
- first_name: Xuesong
  full_name: Wu, Xuesong
  last_name: Wu
external_id:
  isi:
  - '000709087600051'
intvolume: '        38'
isi: 1
language:
- iso: eng
month: '01'
oa_version: None
page: 587-598
place: Cham
publication: IUTAM Laminar-Turbulent Transition
publication_identifier:
  eisbn:
  - '9783030679026'
  eissn:
  - 1875-3493
  isbn:
  - '9783030679019'
  issn:
  - 1875-3507
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
series_title: IUTAM Bookseries
status: public
title: Effects of streaky structures on the instability of supersonic boundary layers
type: book_chapter
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 38
year: '2022'
...
---
_id: '9467'
abstract:
- lang: eng
  text: "Turbulence in the flow of fluid through a pipe can be suppressed by buoyancy
    forces. As the suppression of turbulence leads to severe heat transfer deterioration,
    this is an important and undesirable phenomenon in both heating and cooling applications.
    Vertical flow is often considered, as the axial buoyancy force can help drive
    the flow. With heating measured by the buoyancy parameter \U0001D436, our direct
    numerical simulations show that shear-driven turbulence may either be completely
    laminarised or it transitions to a relatively quiescent convection-driven state.
    Buoyancy forces cause a flattening of the base flow profile, which in isothermal
    pipe flow has recently been linked to complete suppression of turbulence (Kühnen
    et al., Nat. Phys., vol. 14, 2018, pp. 386–390), and the flattened laminar base
    profile has enhanced nonlinear stability (Marensi et al., J. Fluid Mech., vol.
    863, 2019, pp. 50–875). In agreement with these findings, the nonlinear lower-branch
    travelling-wave solution analysed here, which is believed to mediate transition
    to turbulence in isothermal pipe flow, is shown to be suppressed by buoyancy.
    A linear instability of the laminar base flow is responsible for the appearance
    of the relatively quiescent convection driven state for \U0001D436≳4 across the
    range of Reynolds numbers considered. In the suppression of turbulence, however,
    i.e. in the transition from turbulence, we find clearer association with the analysis
    of He et al. (J. Fluid Mech., vol. 809, 2016, pp. 31–71) than with the above dynamical
    systems approach, which describes better the transition to turbulence. The laminarisation
    criterion He et al. propose, based on an apparent Reynolds number of the flow
    as measured by its driving pressure gradient, is found to capture the critical
    \U0001D436=\U0001D436\U0001D450\U0001D45F(\U0001D445\U0001D452) above which the
    flow will be laminarised or switch to the convection-driven type. Our analysis
    suggests that it is the weakened rolls, rather than the streaks, which appear
    to be critical for laminarisation."
acknowledgement: The anonymous referees are kindly acknowledged for their useful suggestions
  andcomments.
article_number: A17
article_processing_charge: Yes (via OA deal)
article_type: original
arxiv: 1
author:
- first_name: Elena
  full_name: Marensi, Elena
  id: 0BE7553A-1004-11EA-B805-18983DDC885E
  last_name: Marensi
- first_name: Shuisheng
  full_name: He, Shuisheng
  last_name: He
- first_name: Ashley P.
  full_name: Willis, Ashley P.
  last_name: Willis
citation:
  ama: Marensi E, He S, Willis AP. Suppression of turbulence and travelling waves
    in a vertical heated pipe. <i>Journal of Fluid Mechanics</i>. 2021;919. doi:<a
    href="https://doi.org/10.1017/jfm.2021.371">10.1017/jfm.2021.371</a>
  apa: Marensi, E., He, S., &#38; Willis, A. P. (2021). Suppression of turbulence
    and travelling waves in a vertical heated pipe. <i>Journal of Fluid Mechanics</i>.
    Cambridge University Press. <a href="https://doi.org/10.1017/jfm.2021.371">https://doi.org/10.1017/jfm.2021.371</a>
  chicago: Marensi, Elena, Shuisheng He, and Ashley P. Willis. “Suppression of Turbulence
    and Travelling Waves in a Vertical Heated Pipe.” <i>Journal of Fluid Mechanics</i>.
    Cambridge University Press, 2021. <a href="https://doi.org/10.1017/jfm.2021.371">https://doi.org/10.1017/jfm.2021.371</a>.
  ieee: E. Marensi, S. He, and A. P. Willis, “Suppression of turbulence and travelling
    waves in a vertical heated pipe,” <i>Journal of Fluid Mechanics</i>, vol. 919.
    Cambridge University Press, 2021.
  ista: Marensi E, He S, Willis AP. 2021. Suppression of turbulence and travelling
    waves in a vertical heated pipe. Journal of Fluid Mechanics. 919, A17.
  mla: Marensi, Elena, et al. “Suppression of Turbulence and Travelling Waves in a
    Vertical Heated Pipe.” <i>Journal of Fluid Mechanics</i>, vol. 919, A17, Cambridge
    University Press, 2021, doi:<a href="https://doi.org/10.1017/jfm.2021.371">10.1017/jfm.2021.371</a>.
  short: E. Marensi, S. He, A.P. Willis, Journal of Fluid Mechanics 919 (2021).
date_created: 2021-06-06T22:01:30Z
date_published: 2021-07-25T00:00:00Z
date_updated: 2023-08-08T13:58:41Z
day: '25'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1017/jfm.2021.371
external_id:
  arxiv:
  - '2008.13486'
  isi:
  - '000653785000001'
file:
- access_level: open_access
  checksum: 867ad077e45c181c2c5ec1311ba27c41
  content_type: application/pdf
  creator: kschuh
  date_created: 2021-08-03T09:53:28Z
  date_updated: 2021-08-03T09:53:28Z
  file_id: '9766'
  file_name: 2021_JournalFluidMechanics_Marensi.pdf
  file_size: 4087358
  relation: main_file
  success: 1
file_date_updated: 2021-08-03T09:53:28Z
has_accepted_license: '1'
intvolume: '       919'
isi: 1
language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
publication: Journal of Fluid Mechanics
publication_identifier:
  eissn:
  - '14697645'
  issn:
  - '00221120'
publication_status: published
publisher: Cambridge University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: Suppression of turbulence and travelling waves in a vertical heated pipe
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 919
year: '2021'
...
---
_id: '10203'
abstract:
- lang: eng
  text: Single photon emitters in atomically-thin semiconductors can be deterministically
    positioned using strain induced by underlying nano-structures. Here, we couple
    monolayer WSe2 to high-refractive-index gallium phosphide dielectric nano-antennas
    providing both optical enhancement and monolayer deformation. For single photon
    emitters formed on such nano-antennas, we find very low (femto-Joule) saturation
    pulse energies and up to 104 times brighter photoluminescence than in WSe2 placed
    on low-refractive-index SiO2 pillars. We show that the key to these observations
    is the increase on average by a factor of 5 of the quantum efficiency of the emitters
    coupled to the nano-antennas. This further allows us to gain new insights into
    their photoluminescence dynamics, revealing the roles of the dark exciton reservoir
    and Auger processes. We also find that the coherence time of such emitters is
    limited by intrinsic dephasing processes. Our work establishes dielectric nano-antennas
    as a platform for high-efficiency quantum light generation in monolayer semiconductors.
acknowledgement: L.S., P.G.Z., and A.I.T. thank the financial support of the European
  Graphene Flagship Project under grant agreements 881603 and EPSRC grant EP/S030751/1.
  L.S. and A.I.T. thank the European Union’s Horizon 2020 research and innovation
  programme under ITN Spin-NANO Marie Sklodowska-Curie grant agreement no. 676108.
  P.G.Z. and A.I.T. thank the European Union’s Horizon 2020 research and innovation
  programme under ITN 4PHOTON Marie Sklodowska-Curie grant agreement no. 721394. J.C.,
  S.A.M., and R.S. acknowledge funding by EPSRC (EP/P033369 and EP/M013812). C.L.P.,
  A.J.B., A.I.T., and A.M.F. acknowledge funding by EPSRC Programme Grant EP/N031776/1.
  S.A.M. acknowledges the Lee-Lucas Chair in Physics, the Solar Energies go Hybrid
  (SolTech) programme, and the Deutsche Forschungsgemeinschaft (DFG, German Research
  Foundation) under Germany’s Excellence Strategy - EXC 2089/1 - 390776260.
article_number: '6063'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Luca
  full_name: Sortino, Luca
  last_name: Sortino
- first_name: Panaiot G.
  full_name: Zotev, Panaiot G.
  last_name: Zotev
- first_name: Catherine L.
  full_name: Phillips, Catherine L.
  last_name: Phillips
- first_name: Alistair J.
  full_name: Brash, Alistair J.
  last_name: Brash
- first_name: Javier
  full_name: Cambiasso, Javier
  last_name: Cambiasso
- first_name: Elena
  full_name: Marensi, Elena
  id: 0BE7553A-1004-11EA-B805-18983DDC885E
  last_name: Marensi
  orcid: 0000-0001-7173-4923
- first_name: A. Mark
  full_name: Fox, A. Mark
  last_name: Fox
- first_name: Stefan A.
  full_name: Maier, Stefan A.
  last_name: Maier
- first_name: Riccardo
  full_name: Sapienza, Riccardo
  last_name: Sapienza
- first_name: Alexander I.
  full_name: Tartakovskii, Alexander I.
  last_name: Tartakovskii
citation:
  ama: Sortino L, Zotev PG, Phillips CL, et al. Bright single photon emitters with
    enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric
    nano-antennas. <i>Nature Communications</i>. 2021;12. doi:<a href="https://doi.org/10.1038/s41467-021-26262-3">10.1038/s41467-021-26262-3</a>
  apa: Sortino, L., Zotev, P. G., Phillips, C. L., Brash, A. J., Cambiasso, J., Marensi,
    E., … Tartakovskii, A. I. (2021). Bright single photon emitters with enhanced
    quantum efficiency in a two-dimensional semiconductor coupled with dielectric
    nano-antennas. <i>Nature Communications</i>. Springer Nature. <a href="https://doi.org/10.1038/s41467-021-26262-3">https://doi.org/10.1038/s41467-021-26262-3</a>
  chicago: Sortino, Luca, Panaiot G. Zotev, Catherine L. Phillips, Alistair J. Brash,
    Javier Cambiasso, Elena Marensi, A. Mark Fox, Stefan A. Maier, Riccardo Sapienza,
    and Alexander I. Tartakovskii. “Bright Single Photon Emitters with Enhanced Quantum
    Efficiency in a Two-Dimensional Semiconductor Coupled with Dielectric Nano-Antennas.”
    <i>Nature Communications</i>. Springer Nature, 2021. <a href="https://doi.org/10.1038/s41467-021-26262-3">https://doi.org/10.1038/s41467-021-26262-3</a>.
  ieee: L. Sortino <i>et al.</i>, “Bright single photon emitters with enhanced quantum
    efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas,”
    <i>Nature Communications</i>, vol. 12. Springer Nature, 2021.
  ista: Sortino L, Zotev PG, Phillips CL, Brash AJ, Cambiasso J, Marensi E, Fox AM,
    Maier SA, Sapienza R, Tartakovskii AI. 2021. Bright single photon emitters with
    enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric
    nano-antennas. Nature Communications. 12, 6063.
  mla: Sortino, Luca, et al. “Bright Single Photon Emitters with Enhanced Quantum
    Efficiency in a Two-Dimensional Semiconductor Coupled with Dielectric Nano-Antennas.”
    <i>Nature Communications</i>, vol. 12, 6063, Springer Nature, 2021, doi:<a href="https://doi.org/10.1038/s41467-021-26262-3">10.1038/s41467-021-26262-3</a>.
  short: L. Sortino, P.G. Zotev, C.L. Phillips, A.J. Brash, J. Cambiasso, E. Marensi,
    A.M. Fox, S.A. Maier, R. Sapienza, A.I. Tartakovskii, Nature Communications 12
    (2021).
date_created: 2021-10-31T23:01:30Z
date_published: 2021-10-18T00:00:00Z
date_updated: 2023-08-14T08:12:12Z
day: '18'
ddc:
- '530'
department:
- _id: BjHo
doi: 10.1038/s41467-021-26262-3
external_id:
  arxiv:
  - '2103.16986'
  isi:
  - '000708601800015'
file:
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publication: Nature Communications
publication_identifier:
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publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
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title: Bright single photon emitters with enhanced quantum efficiency in a two-dimensional
  semiconductor coupled with dielectric nano-antennas
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