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@PHDTHESIS{Luo:640323,
author = {Luo, Cheng},
othercontributors = {Laarmann, Tim and Drescher, Markus},
title = {{H}igh-power {F}ew-cycle {MID}-{IR} {P}ulse {G}eneration
for {V}ibrational {S}pectroscopy},
school = {University of Hamburg},
type = {Dissertation},
reportid = {PUBDB-2025-04774},
pages = {101},
year = {2025},
note = {Dissertation, University of Hamburg, 2025},
abstract = {High-power, high-energy, ultrashort, mid-infrared (MID-IR)
laser systems operating at high repetition rates are of
significant interest for coherent vibrational spectroscopy
investigations within the "fingerprint region'' (6-16 um).
First of all, the optical properties of Li-based nonlinear
crystals (NLC) for MID-IR generation are evaluated under
high power laser irradiation at $1030\,nm$ central
wavelength using a thermal imaging method. It turns out that
lithium gallium sulfide (LGS) crystal exhibits a relatively
low linear absorption coefficient < 0.002 $cm^{-1},$ the
lowest nonlinear absorption coefficient < 3.2 x $10^{-4}$
cm/W and a nonlinear refractive index < 6.4 x $10^{-15}$
$cm^{2}/W,$ positioning it as a highly promising material
candidate for MID-IR optical parametric chirped-pulse
amplifier (OPCPA) applications.Based on the LGS crystal, a
versatile design of a MID-IR OPCPA laser system is
developed, featuring two complementary operation modes
differ that in the group-delay dispersion (GDD) of the
signal pulse. One scheme provides a wavelength-tunable
source (from 4.2 to 11 um) at ~ 1 ps pulse width, while the
other scheme generates a broadband pulse (from 7 to 11 um)
centered at 9 um with 114 fs pulse duration, which
corresponds to about 3 optical cycles. Both MID-IR laser
operation modes exhibit high average power exceeding 200 mW
and high pulse energy of 1.2 uJ operating at 200 kHz, having
significant potential for vibrational spectroscopy and
microscopy making use of characteristic molecular
fingerprints in the MID-IR spectral range.Moreover, by
utilizing the broadband ultrashort MID-IR pulse, the
ultra-broadband vibrational sum-frequency generation
(BB-VSFG) spectroscopy is demonstrated using glucose pellets
as a proof-of-principle sample, revealing 8 characteristic
vibrational modes spanning from 800 to 1400 $cm^{-1}.$
Notably, the carbon-oxygen bond stretching mode at 1035
$cm^{-1}$ shows high sensitivity to biologically relevant 10
mM of glucose solution in the VSFG spectra. Consequently,
this methodology holds promise for blood sugar monitoring in
diabetic individuals.},
cin = {FS-PS},
cid = {I:(DE-H253)FS-PS-20131107},
pnm = {631 - Matter – Dynamics, Mechanisms and Control
(POF4-631) / AIM, DFG project G:(GEPRIS)390715994 - EXC
2056: CUI: Advanced Imaging of Matter (390715994)},
pid = {G:(DE-HGF)POF4-631 / G:(GEPRIS)390715994},
experiment = {EXP:(DE-MLZ)NOSPEC-20140101},
typ = {PUB:(DE-HGF)11},
urn = {urn:nbn:de:gbv:18-ediss-126621},
doi = {10.3204/PUBDB-2025-04774},
url = {https://bib-pubdb1.desy.de/record/640323},
}