Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The mechanism of high harmonic generation in liquid alcohol   The observation of non-perturbative harmonic emission in solids from
ultrashort laser pulses [1] sparked a wave of studies [2,3] as a probe of
charge carrier dynamics in solids under strong fields and a route to extreme
ultraviolet (XUV) attosecond photonic devices [4]. High harmonic generation
(HHG) in liquids [5,6] is far less explored, despite their relevance to
biological media, and the mechanism is hotly debated. Using few-cycle pulses
below the breakdown threshold, we demonstrate HHG in alcohol with data showing
carrier-envelope-phase-dependent XUV spectra extending to 50 eV from
isopropanol. We study the mechanism of the harmonic emission through its
dependence on the driving field and find it to be consistent with a
strong-field recombination mechanism. This maps emitted photon energy to the
electron trajectories. We explore the role of the liquid environment in
scattering the trajectories and find evidence that information on electron
scattering from neighbouring molecules is encoded in the harmonic spectra.
Using simulations we exploit this to estimate the scattering cross section and
we confirm that the cross-section in liquid isopropanol is significantly
reduced compared to vapour. Our findings suggest an \textit{in situ}
measurement strategy for retrieving accurate values of scattering cross
sections in liquids, and also a pathway to liquid-based attosecond XUV devices.

22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int