Soliton
dynamics
can
be
used
for
compressing
optical
pulses
to
few
fs
durations
over
a
wide
spectral
range,
and
conveniently
scaled
in
gas-filled
hollow-core
fibre
by
suitable
design
of
the
structure
choice
gas
[1]
,
[2]
.
In
this
fashion,
similar
patterns
pulse
propagation
obtained
at
energies
ranging
from
tens
nJ
up
mJ-level,
τ
0
hundreds
fs.
The
are
controlled
soliton
order
N
distance
frequency
ν
zero
dispersion
ZD
Here
we
report
existence
region
(
)-space
where
soliton-effect
self-compression
is
optimal,
provided
transmission
loss
negligible.
We
assess
limits
set
modulational
instability
(MI)
[3]
self-focusing
(SF),
photoionisation
(ION)
derive
new
limit
third-order
(TOD).
By
numerical
simulation
(not
shown)
validate
these
limits,
observing
that
if
they
exceeded
compression
quality
degrades.
Furthermore,
investigate,
both
theoretically
experimentally,
scaling
MHz-level
repetition
rates,
when
inter-pulse
effects
cannot
neglected.
We
have
lowered
the
pump
energy
threshold
for
generation
of
tuneable
deep-ultraviolet
pulses
to
tens
nano-joules
level
by
pumping
a
record
small-core
anti-resonant
fiber
with
hollow
core
diameter
just
6
μm.
We
have
lowered
the
pump
energy
threshold
for
generation
of
tuneable
deep-ultraviolet
pulses
to
tens
nano-joules
level
by
pumping
a
record
small-core
anti-resonant
fiber
with
hollow
core
diameter
just
6
μm.
We
have
lowered
the
pump
energy
threshold
for
generation
of
tuneable
deep-ultraviolet
pulses
to
tens
nano-joules
level
by
pumping
a
record
small-core
anti-resonant
fiber
with
hollow
core
diameter
just
6
μm.
We
have
lowered
the
pump
energy
threshold
for
generation
of
tuneable
deep-ultraviolet
pulses
to
tens
nano-joules
level
by
pumping
a
record
small-core
anti-resonant
fiber
with
hollow
core
diameter
just
6
μm.
Abstract
The
underlying
mechanism
of
broadband
dispersive‐wave
emission
within
a
resonance
band
gas‐filled
anti‐resonant
hollow‐core
fiber
is
studied.
Both
numerical
and
experimental
results
unveiled
that
the
pump
pulse
with
soliton
order
≈3,
launched
into
fiber,
experienced
two
stages
compression,
resulting
in
multi‐peak
structure
emitted
spectrum.
Over
first‐stage
sharp
increase
peak
power
triggers
first
time
emission,
simultaneously
causes
frequency
blue‐shift
due
to
soliton‐plasma
interactions.
As
central
blue‐shifting
approaches
it
experiences
fast‐decreasing
dispersion
value
waveguide,
second
stage
compression.
second‐stage
compression
phase‐matched
slightly
lower
than
at
stage.
Multi‐peak
spectra
output
dispersive‐waves
their
formation
dynamics
can
be
understood
using
delicate
unique
coupling
among
three
nonlinear
effects
including
multi‐stage
interaction,
emission.
dispersive‐wave,
exhibiting
good
coherence
stability,
potentially
compressed
sub‐30
fs
duration
precise
chirp‐compensation
technique.
Gas-based
systems
(e.g.
based
on
hollow-core
fibres)
are
extensively
used
over
a
wide
spectral
range
to
temporally
compress
ultrashort
pulses.
Recent
progress
in
solid-state
lasers
and
compression
schemes
has
enabled
the
generation
of
sub-femtosecond
pulses
at
unprecedented
energies
average
powers
[1]
–
[3]
.
However,
latest
deliver
mJ
hundreds-of-kHz
repetition
rates
[4]
,
which
raises
new
challenges
for
gas-based
pulse
compression.
At
high
rates,
even
weak
single-shot
energy
deposition
gas
by
ionisation-driven
heating)
is
sufficient
cause
transversely
non-uniform
density
depression
build
up
pulse-by-pulse
[5]
leading
thermal
instabilities.
Using
lighter
noble
gases
often
insufficient
mitigate
this,
despite
weaker
nonlinear
absorption.
This
because
nonlinearity
broadening
requires
substantially
higher
pressures,
resulting
much
slower
relaxation
(the
diffusivity
scales
inversely
with
density).
arXiv (Cornell University),
Journal Year:
2022,
Volume and Issue:
unknown
Published: Jan. 1, 2022
We
combine
soliton
dynamics
in
gas-filled
hollow-core
photonic
crystal
fibers
with
a
state-of-the-art
fiber
laser
to
realize
turn-key
system
producing
few-fs
pulses
at
8
MHz
repetition
rate
pump
energies
as
low
220
nJ.
Furthermore,
by
exploiting
the
self-frequency
shift
second
hydrogen-filled
fiber,
we
efficiently
generate
short
22
fs,
continuously
tunable
from
1100
nm
1474
nm.
Soliton
dynamics
can
be
used
for
compressing
optical
pulses
to
few
fs
durations
over
a
wide
spectral
range,
and
conveniently
scaled
in
gas-filled
hollow-core
fibre
by
suitable
design
of
the
structure
choice
gas
[1]
,
[2]
.
In
this
fashion,
similar
patterns
pulse
propagation
obtained
at
energies
ranging
from
tens
nJ
up
mJ-level,
τ
0
hundreds
fs.
The
are
controlled
soliton
order
N
distance
frequency
ν
zero
dispersion
ZD
Here
we
report
existence
region
(
)-space
where
soliton-effect
self-compression
is
optimal,
provided
transmission
loss
negligible.
We
assess
limits
set
modulational
instability
(MI)
[3]
self-focusing
(SF),
photoionisation
(ION)
derive
new
limit
third-order
(TOD).
By
numerical
simulation
(not
shown)
validate
these
limits,
observing
that
if
they
exceeded
compression
quality
degrades.
Furthermore,
investigate,
both
theoretically
experimentally,
scaling
MHz-level
repetition
rates,
when
inter-pulse
effects
cannot
neglected.
