---
_id: '14886'
abstract:
- lang: eng
  text: It is a basic principle that an effect cannot come before the cause. Dispersive
    relations that follow from this fundamental fact have proven to be an indispensable
    tool in physics and engineering. They are most powerful in the domain of linear
    response where they are known as Kramers-Kronig relations. However, when it comes
    to nonlinear phenomena the implications of causality are much less explored, apart
    from several notable exceptions. Here in this paper we demonstrate how to apply
    the dispersive formalism to analyze the ultrafast nonlinear response in the context
    of the paradigmatic nonlinear Kerr effect. We find that the requirement of causality
    introduces a noticeable effect even under assumption that Kerr effect is mediated
    by quasi-instantaneous off-resonant electronic hyperpolarizability. We confirm
    this by experimentally measuring the time-resolved Kerr dynamics in GaAs by means
    of a hybrid pump-probe Mach-Zehnder interferometer and demonstrate the presence
    of an intrinsic lagging between amplitude and phase responses as predicted by
    dispersive analysis. Our results describe a general property of the time-resolved
    nonlinear processes thereby highlighting the importance of accounting for dispersive
    effects in the nonlinear optical processes involving ultrashort pulses.
acknowledgement: The work was supported by the Institute of Science and Technology
  Austria (ISTA). We thank Prof. John M. Dudley, Dr. Ugur Sezer, and Dr. Artem Volosniev
  for valuable discussions.
article_number: '013042'
article_processing_charge: Yes
article_type: original
author:
- first_name: Dusan
  full_name: Lorenc, Dusan
  id: 40D8A3E6-F248-11E8-B48F-1D18A9856A87
  last_name: Lorenc
- first_name: Zhanybek
  full_name: Alpichshev, Zhanybek
  id: 45E67A2A-F248-11E8-B48F-1D18A9856A87
  last_name: Alpichshev
  orcid: 0000-0002-7183-5203
citation:
  ama: 'Lorenc D, Alpichshev Z. Dispersive effects in ultrafast nonlinear phenomena:
    The case of optical Kerr effect. <i>Physical Review Research</i>. 2024;6(1). doi:<a
    href="https://doi.org/10.1103/PhysRevResearch.6.013042">10.1103/PhysRevResearch.6.013042</a>'
  apa: 'Lorenc, D., &#38; Alpichshev, Z. (2024). Dispersive effects in ultrafast nonlinear
    phenomena: The case of optical Kerr effect. <i>Physical Review Research</i>. American
    Physical Society. <a href="https://doi.org/10.1103/PhysRevResearch.6.013042">https://doi.org/10.1103/PhysRevResearch.6.013042</a>'
  chicago: 'Lorenc, Dusan, and Zhanybek Alpichshev. “Dispersive Effects in Ultrafast
    Nonlinear Phenomena: The Case of Optical Kerr Effect.” <i>Physical Review Research</i>.
    American Physical Society, 2024. <a href="https://doi.org/10.1103/PhysRevResearch.6.013042">https://doi.org/10.1103/PhysRevResearch.6.013042</a>.'
  ieee: 'D. Lorenc and Z. Alpichshev, “Dispersive effects in ultrafast nonlinear phenomena:
    The case of optical Kerr effect,” <i>Physical Review Research</i>, vol. 6, no.
    1. American Physical Society, 2024.'
  ista: 'Lorenc D, Alpichshev Z. 2024. Dispersive effects in ultrafast nonlinear phenomena:
    The case of optical Kerr effect. Physical Review Research. 6(1), 013042.'
  mla: 'Lorenc, Dusan, and Zhanybek Alpichshev. “Dispersive Effects in Ultrafast Nonlinear
    Phenomena: The Case of Optical Kerr Effect.” <i>Physical Review Research</i>,
    vol. 6, no. 1, 013042, American Physical Society, 2024, doi:<a href="https://doi.org/10.1103/PhysRevResearch.6.013042">10.1103/PhysRevResearch.6.013042</a>.'
  short: D. Lorenc, Z. Alpichshev, Physical Review Research 6 (2024).
date_created: 2024-01-28T23:01:42Z
date_published: 2024-01-11T00:00:00Z
date_updated: 2024-01-31T12:01:16Z
day: '11'
ddc:
- '530'
department:
- _id: ZhAl
doi: 10.1103/PhysRevResearch.6.013042
file:
- access_level: open_access
  checksum: 42d58f93ae74e7f2c4de058ef75ff8b2
  content_type: application/pdf
  creator: dernst
  date_created: 2024-01-31T11:59:30Z
  date_updated: 2024-01-31T11:59:30Z
  file_id: '14918'
  file_name: 2024_PhysicalReviewResearch_Lorenc.pdf
  file_size: 2863627
  relation: main_file
  success: 1
file_date_updated: 2024-01-31T11:59:30Z
has_accepted_license: '1'
intvolume: '         6'
issue: '1'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
publication: Physical Review Research
publication_identifier:
  eissn:
  - 2643-1564
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Dispersive effects in ultrafast nonlinear phenomena: The case of optical Kerr
  effect'
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: 6
year: '2024'
...
---
_id: '14980'
abstract:
- lang: eng
  text: Precision sensing and manipulation of milligram-scale mechanical oscillators
    has attracted growing interest in the fields of table-top explorations of gravity
    and tests of quantum mechanics at macroscopic scales. Torsional oscillators present
    an opportunity in this regard due to their remarked isolation from environmental
    noise. For torsional motion, an effective employment of optical cavities to enhance
    optomechanical interactions—as already established for linear oscillators—so far
    faced certain challenges. Here, we propose a concept for sensing and manipulating
    torsional motion, where exclusively the torsional rotations of a pendulum are
    mapped onto the path length of a single two-mirror optical cavity. The concept
    inherently alleviates many limitations of previous approaches. A proof-of-principle
    experiment is conducted with a rigidly controlled pendulum to explore the sensing
    aspects of the concept and to identify practical limitations in a potential state-of-the
    art setup. Based on this study, we anticipate development of precision torque
    sensors utilizing torsional pendulums that can support sensitivities below 10−19Nm/√Hz,
    while the motion of the pendulums are dominated by quantum radiation pressure
    noise at sub-microwatts of incoming laser power. These developments will provide
    horizons for experiments at the interface of quantum mechanics and gravity.
acknowledgement: "We thank Pere Rosselló for his contributions to the initial modeling
  of the presented sensing technique. This work was supported by Institute of Science
  and Technology Austria, and\r\nthe European Research Council under Grant No. 101087907
  (ERC CoG QuHAMP)."
article_number: '013141'
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Sofya
  full_name: Agafonova, Sofya
  id: 09501ff6-dca7-11ea-a8ae-b3e0b9166e80
  last_name: Agafonova
  orcid: 0000-0003-0582-2946
- first_name: Umang
  full_name: Mishra, Umang
  id: 4328fa4c-f128-11eb-9611-c107b0fe4d51
  last_name: Mishra
- first_name: Fritz R
  full_name: Diorico, Fritz R
  id: 2E054C4C-F248-11E8-B48F-1D18A9856A87
  last_name: Diorico
  orcid: 0000-0002-4947-8924
- first_name: Onur
  full_name: Hosten, Onur
  id: 4C02D85E-F248-11E8-B48F-1D18A9856A87
  last_name: Hosten
  orcid: 0000-0002-2031-204X
citation:
  ama: Agafonova S, Mishra U, Diorico FR, Hosten O. Zigzag optical cavity for sensing
    and controlling torsional motion. <i>Physical Review Research</i>. 2024;6(1).
    doi:<a href="https://doi.org/10.1103/physrevresearch.6.013141">10.1103/physrevresearch.6.013141</a>
  apa: Agafonova, S., Mishra, U., Diorico, F. R., &#38; Hosten, O. (2024). Zigzag
    optical cavity for sensing and controlling torsional motion. <i>Physical Review
    Research</i>. American Physical Society. <a href="https://doi.org/10.1103/physrevresearch.6.013141">https://doi.org/10.1103/physrevresearch.6.013141</a>
  chicago: Agafonova, Sofya, Umang Mishra, Fritz R Diorico, and Onur Hosten. “Zigzag
    Optical Cavity for Sensing and Controlling Torsional Motion.” <i>Physical Review
    Research</i>. American Physical Society, 2024. <a href="https://doi.org/10.1103/physrevresearch.6.013141">https://doi.org/10.1103/physrevresearch.6.013141</a>.
  ieee: S. Agafonova, U. Mishra, F. R. Diorico, and O. Hosten, “Zigzag optical cavity
    for sensing and controlling torsional motion,” <i>Physical Review Research</i>,
    vol. 6, no. 1. American Physical Society, 2024.
  ista: Agafonova S, Mishra U, Diorico FR, Hosten O. 2024. Zigzag optical cavity for
    sensing and controlling torsional motion. Physical Review Research. 6(1), 013141.
  mla: Agafonova, Sofya, et al. “Zigzag Optical Cavity for Sensing and Controlling
    Torsional Motion.” <i>Physical Review Research</i>, vol. 6, no. 1, 013141, American
    Physical Society, 2024, doi:<a href="https://doi.org/10.1103/physrevresearch.6.013141">10.1103/physrevresearch.6.013141</a>.
  short: S. Agafonova, U. Mishra, F.R. Diorico, O. Hosten, Physical Review Research
    6 (2024).
date_created: 2024-02-12T11:42:18Z
date_published: 2024-02-05T00:00:00Z
date_updated: 2024-02-12T11:49:06Z
day: '05'
ddc:
- '530'
department:
- _id: OnHo
doi: 10.1103/physrevresearch.6.013141
external_id:
  arxiv:
  - '2306.12804'
file:
- access_level: open_access
  checksum: 3a39ebffb24c1cc1dd0b547a726dc52d
  content_type: application/pdf
  creator: dernst
  date_created: 2024-02-12T11:46:50Z
  date_updated: 2024-02-12T11:46:50Z
  file_id: '14981'
  file_name: 2024_PhysicalRevResearch_Agafonova.pdf
  file_size: 1437167
  relation: main_file
  success: 1
file_date_updated: 2024-02-12T11:46:50Z
has_accepted_license: '1'
intvolume: '         6'
issue: '1'
language:
- iso: eng
month: '02'
oa: 1
oa_version: Published Version
project:
- _id: bdb2a702-d553-11ed-ba76-f12e3e5a3bc6
  grant_number: '101087907'
  name: 'A quantum hybrid of atoms and milligram-scale pendulums: towards gravitational
    quantum mechanics'
publication: Physical Review Research
publication_identifier:
  eissn:
  - 2643-1564
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
status: public
title: Zigzag optical cavity for sensing and controlling torsional motion
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: 6
year: '2024'
...
