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Field-resolved high-order sub- cycle nonlinearities in a terahertz semiconductor laser,

Riepl, J ; Raab, J. ; Abajyan, P. ; paris, sorbonne ; Freeman, J.R. ; Li, L.H. ; Linfield, E.H. ; Davies, A.G. ; Wacker, Andreas LU orcid and Albes, T. , et al. (2021) In Light, science & applications 10(1). p.246-246
Abstract
The exploitation of ultrafast electron dynamics in quantum cascade lasers (QCLs) holds enormous potential for
intense, compact mode-locked terahertz (THz) sources, squeezed THz light, frequency mixers, and comb-based
metrology systems. Yet the important sub-cycle dynamics have been notoriously difficult to access in operational
THz QCLs. Here, we employ high-field THz pulses to perform the first ultrafast two-dimensional spectroscopy of a
free-running THz QCL. Strong incoherent and coherent nonlinearities up to eight-wave mixing are detected below
and above the laser threshold. These data not only reveal extremely short gain recovery times of 2 ps at the laser
threshold, they also reflect the nonlinear polarization... (More)
The exploitation of ultrafast electron dynamics in quantum cascade lasers (QCLs) holds enormous potential for
intense, compact mode-locked terahertz (THz) sources, squeezed THz light, frequency mixers, and comb-based
metrology systems. Yet the important sub-cycle dynamics have been notoriously difficult to access in operational
THz QCLs. Here, we employ high-field THz pulses to perform the first ultrafast two-dimensional spectroscopy of a
free-running THz QCL. Strong incoherent and coherent nonlinearities up to eight-wave mixing are detected below
and above the laser threshold. These data not only reveal extremely short gain recovery times of 2 ps at the laser
threshold, they also reflect the nonlinear polarization dynamics of the QCL laser transition for the first time, where we
quantify the corresponding dephasing times between 0.9 and 1.5 ps with increasing bias currents. A density-matrix
approach reproducing the emergence of all nonlinearities and their ultrafast evolution, simultaneously, allows us to
map the coherently induced trajectory of the Bloch vector. The observed high-order multi-wave mixing nonlinearities
benefit from resonant enhancement in the absence of absorption losses and bear potential for a number of future
applications, ranging from efficient intracavity frequency conversion, mode proliferation to passive mode locking. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Light, science & applications
volume
10
issue
1
pages
10 pages
publisher
Nature Publishing Group
external identifiers
  • pmid:34924564
  • scopus:85121555613
ISSN
2047-7538
DOI
10.1038/s41377-021-00685-5
project
Quantum Cascade Lasers beyond general paradigms
language
English
LU publication?
yes
id
ea92f626-bf4f-498b-a940-e1aa66402298
date added to LUP
2022-01-18 10:31:27
date last changed
2023-11-09 03:10:43
@article{ea92f626-bf4f-498b-a940-e1aa66402298,
  abstract     = {{The exploitation of ultrafast electron dynamics in quantum cascade lasers (QCLs) holds enormous potential for<br/>intense, compact mode-locked terahertz (THz) sources, squeezed THz light, frequency mixers, and comb-based<br/>metrology systems. Yet the important sub-cycle dynamics have been notoriously difficult to access in operational<br/>THz QCLs. Here, we employ high-field THz pulses to perform the first ultrafast two-dimensional spectroscopy of a<br/>free-running THz QCL. Strong incoherent and coherent nonlinearities up to eight-wave mixing are detected below<br/>and above the laser threshold. These data not only reveal extremely short gain recovery times of 2 ps at the laser<br/>threshold, they also reflect the nonlinear polarization dynamics of the QCL laser transition for the first time, where we<br/>quantify the corresponding dephasing times between 0.9 and 1.5 ps with increasing bias currents. A density-matrix<br/>approach reproducing the emergence of all nonlinearities and their ultrafast evolution, simultaneously, allows us to<br/>map the coherently induced trajectory of the Bloch vector. The observed high-order multi-wave mixing nonlinearities<br/>benefit from resonant enhancement in the absence of absorption losses and bear potential for a number of future<br/>applications, ranging from efficient intracavity frequency conversion, mode proliferation to passive mode locking.}},
  author       = {{Riepl, J and Raab, J. and Abajyan, P. and paris, sorbonne and Freeman, J.R. and Li, L.H. and Linfield, E.H. and Davies, A.G. and Wacker, Andreas and Albes, T. and Jirauschek, C. and Lange, C. and Dhillon, S.S. and Huber, R.}},
  issn         = {{2047-7538}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{246--246}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Light, science & applications}},
  title        = {{Field-resolved high-order sub- cycle nonlinearities in a terahertz semiconductor laser,}},
  url          = {{http://dx.doi.org/10.1038/s41377-021-00685-5}},
  doi          = {{10.1038/s41377-021-00685-5}},
  volume       = {{10}},
  year         = {{2021}},
}