Time-gated optical-parametric-amplification and field-resolved detection of mid-infrared free-induction decay signals
Abstract
Infrared spectroscopy is a key tool to study complex structural dynamics in molecular systems. However, resolving weak or broad vibrational modes is challenging due to their rapid decay. Here, we demonstrate a technique to significantly extend the detectable lifetime - and thereby spectral resolution - of molecular signatures by employing synchronized time-gated optical parametric amplification of mid-infrared free-induction decay signals. Utilizing a Cr:ZnS laser system and a nonlinear ZnGeP2 crystal, we achieve a 10-fold increase in the electric field strength of the infrared molecular signal, yielding a two-orders of magnitude enhancement in dynamic range and a 2-fold increase in the signal-to-noise ratio. Using isopropyl alcohol as a model system, we demonstrate that OPA-enhanced detection extends the observable window of vibrational modes up to 72 %. This approach allows for the reconstruction of high-fidelity molecular fingerprints that resolve complex vibrational relaxation pathways and weak structural dynamics, previously hidden within the background and noise, providing a pathway for new high-sensitivity and time-resolved studies of complex chemical structures.
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BibTeX
@misc{revuelta2026timegated,
title = {{Time-gated optical-parametric-amplification and field-resolved detection of mid-infrared free-induction decay signals}},
author = {Sergio Revuelta and Gerard Faustino and Ka Fai Mak and Ferenc Krausz and Nicholas Karpowicz},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.09783},
eprint = {2611.09783},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.09783},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Time-gated optical-parametric-amplification and field-resolved detection of mid-infrared free-induction decay signals
AU - Sergio Revuelta
AU - Gerard Faustino
AU - Ka Fai Mak
AU - Ferenc Krausz
AU - Nicholas Karpowicz
PY - 2026
DA - 2026/11/06
PB - arXiv
DO - 10.48550/arxiv.2611.09783
UR - https://arxiv.org/abs/2611.09783
AB - Infrared spectroscopy is a key tool to study complex structural dynamics in molecular systems. However, resolving weak or broad vibrational modes is challenging due to their rapid decay. Here, we demonstrate a technique to significantly extend the detectable lifetime - and thereby spectral resolution - of molecular signatures by employing synchronized time-gated optical parametric amplification of mid-infrared free-induction decay signals. Utilizing a Cr:ZnS laser system and a nonlinear ZnGeP2 crystal, we achieve a 10-fold increase in the electric field strength of the infrared molecular signal, yielding a two-orders of magnitude enhancement in dynamic range and a 2-fold increase in the signal-to-noise ratio. Using isopropyl alcohol as a model system, we demonstrate that OPA-enhanced detection extends the observable window of vibrational modes up to 72 %. This approach allows for the reconstruction of high-fidelity molecular fingerprints that resolve complex vibrational relaxation pathways and weak structural dynamics, previously hidden within the background and noise, providing a pathway for new high-sensitivity and time-resolved studies of complex chemical structures.
ER -