---
OA_place: publisher
OA_type: hybrid
PlanS_conform: '1'
_id: '21469'
abstract:
- lang: eng
  text: "Terahertz (THz) spectroscopy is a powerful probe of low-energy excitations
    in complex materials. Extending it into the nonlinear regime broadens its scope
    and can provide valuable insight into interactions among these modes. However,
    interpreting nonlinear spectra is challenging because resonant features in this
    case do not always reflect intrinsic material dynamics. Here, we study nonlinear
    THz-induced Kerr effect in a generic material LaAlO3. After detailed analysis
    of temporal oscillations of the Kerr signal, we identify an \U0001D438\U0001D454
    Raman mode at 1.1 THz excited through a two-photon process, while two additional
    peaks (0.86 and 0.36 THz) arise from phase matching of the near-infrared probe
    beam with co- and counterpropagating THz pump fields, mediated by off-resonant
    electronic hyperpolarizability. These results demonstrate the crucial role of
    kinematic effects in shaping THz-induced Kerr response and establish a framework
    for interpreting nonlinear spectroscopies in complex materials."
acknowledgement: Z. A. acknowledges support from the collaborative research project
  SFB Q-M&S funded by the Austrian Science Fund (FWF, Grant No. PR1050F8602). S. F. M.
  acknowledges support and funding from the Deutsche Forschungsgemeinschaft (DFG,
  Grant No. 469405347).
article_number: '106901'
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Chao
  full_name: Shen, Chao
  id: f84c083e-dc8d-11ea-abe3-aaf3d822a8bb
  last_name: Shen
- first_name: Maximilian
  full_name: Frenzel, Maximilian
  last_name: Frenzel
- first_name: Sebastian F.
  full_name: Maehrlein, Sebastian F.
  last_name: Maehrlein
- first_name: Zhanybek
  full_name: Alpichshev, Zhanybek
  id: 45E67A2A-F248-11E8-B48F-1D18A9856A87
  last_name: Alpichshev
  orcid: 0000-0002-7183-5203
citation:
  ama: Shen C, Frenzel M, Maehrlein SF, Alpichshev Z. Disentangling electronic and
    ionic nonlinear polarization effects in bulk THz Kerr response. <i>Physical Review
    Letters</i>. 2026;136(10). doi:<a href="https://doi.org/10.1103/1c5k-9z82">10.1103/1c5k-9z82</a>
  apa: Shen, C., Frenzel, M., Maehrlein, S. F., &#38; Alpichshev, Z. (2026). Disentangling
    electronic and ionic nonlinear polarization effects in bulk THz Kerr response.
    <i>Physical Review Letters</i>. American Physical Society. <a href="https://doi.org/10.1103/1c5k-9z82">https://doi.org/10.1103/1c5k-9z82</a>
  chicago: Shen, Chao, Maximilian Frenzel, Sebastian F. Maehrlein, and Zhanybek Alpichshev.
    “Disentangling Electronic and Ionic Nonlinear Polarization Effects in Bulk THz
    Kerr Response.” <i>Physical Review Letters</i>. American Physical Society, 2026.
    <a href="https://doi.org/10.1103/1c5k-9z82">https://doi.org/10.1103/1c5k-9z82</a>.
  ieee: C. Shen, M. Frenzel, S. F. Maehrlein, and Z. Alpichshev, “Disentangling electronic
    and ionic nonlinear polarization effects in bulk THz Kerr response,” <i>Physical
    Review Letters</i>, vol. 136, no. 10. American Physical Society, 2026.
  ista: Shen C, Frenzel M, Maehrlein SF, Alpichshev Z. 2026. Disentangling electronic
    and ionic nonlinear polarization effects in bulk THz Kerr response. Physical Review
    Letters. 136(10), 106901.
  mla: Shen, Chao, et al. “Disentangling Electronic and Ionic Nonlinear Polarization
    Effects in Bulk THz Kerr Response.” <i>Physical Review Letters</i>, vol. 136,
    no. 10, 106901, American Physical Society, 2026, doi:<a href="https://doi.org/10.1103/1c5k-9z82">10.1103/1c5k-9z82</a>.
  short: C. Shen, M. Frenzel, S.F. Maehrlein, Z. Alpichshev, Physical Review Letters
    136 (2026).
corr_author: '1'
date_created: 2026-03-22T23:04:31Z
date_published: 2026-03-13T00:00:00Z
date_updated: 2026-03-23T13:11:09Z
day: '13'
ddc:
- '530'
department:
- _id: ZhAl
- _id: GradSch
doi: 10.1103/1c5k-9z82
file:
- access_level: open_access
  checksum: 712b05b4b0e0fbe9fd426a8c9d41ce20
  content_type: application/pdf
  creator: dernst
  date_created: 2026-03-23T13:08:06Z
  date_updated: 2026-03-23T13:08:06Z
  file_id: '21475'
  file_name: 2026_PhysicalReviewLetters_Shen.pdf
  file_size: 1375532
  relation: main_file
  success: 1
file_date_updated: 2026-03-23T13:08:06Z
has_accepted_license: '1'
intvolume: '       136'
issue: '10'
language:
- iso: eng
month: '03'
oa: 1
oa_version: Published Version
project:
- _id: 34a97cc6-11ca-11ed-8bc3-9acbba792f33
  grant_number: F8602
  name: 'Center for Correlated Quantum Materials and Solid State Quantum Systems:
    Nonlinear THz spectroscopy of quantum critical materials'
publication: Physical Review Letters
publication_identifier:
  eissn:
  - 1079-7114
  issn:
  - 0031-9007
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Disentangling electronic and ionic nonlinear polarization effects in bulk THz
  Kerr response
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: 136
year: '2026'
...