Theoretical model of passive mode-locking in terahertz quantum cascade lasers with distributed saturable absorbers
Nanophotonics,
Journal Year:
2024,
Volume and Issue:
13(10), P. 1823 - 1834
Published: Feb. 1, 2024
In
research
and
engineering,
short
laser
pulses
are
fundamental
for
metrology
communication.
The
generation
of
by
passive
mode-locking
is
especially
desirable
due
to
the
compact
setup
dimensions,
without
need
active
modulation
requiring
dedicated
external
circuitry.
However,
well-established
models
do
not
cover
regular
self-pulsing
in
gain
media
that
recover
faster
than
cavity
round
trip
time.
For
quantum
cascade
lasers
(QCLs),
this
marked
a
significant
limitation
their
operation,
as
they
exhibit
picosecond
dynamics
associated
with
intersubband
transitions.
We
present
model
gives
detailed
insights
into
pulse
first
passively
mode-locked
QCL
was
recently
demonstrated.
presence
an
incoherent
saturable
absorber,
exemplarily
realized
multilayer
graphene
distributed
along
cavity,
drives
pulsed
state
exhibiting
similarly
fast
recovery
time
medium.
This
previously
unstudied
operation
reveals
remarkable
response
medium
on
unevenly
intracavity
intensity.
show
strong
spatial
hole
burning
medium,
stabilizes
itself
suppressing
counter-propagating
light
getting
shortened
again
at
facets.
Finally,
we
study
robustness
respect
absorber
properties
identify
strategies
generating
even
shorter
pulses.
obtained
results
may
also
have
implications
other
nanostructured
sources,
example,
based
dots.
Language: Английский
Modeling of fluctuations in dynamical optoelectronic device simulations within a Maxwell-density matrix Langevin approach
Deleted Journal,
Journal Year:
2024,
Volume and Issue:
1(1)
Published: March 1, 2024
We
present
a
full-wave
Maxwell-density
matrix
simulation
tool
including
c-number
stochastic
noise
terms
for
the
modeling
of
spatiotemporal
dynamics
in
active
photonic
devices,
such
as
quantum
cascade
lasers
and
dot
structures.
The
coherent
light–matter
interaction
devices
plays
an
important
role
generation
frequency
combs
other
nonlinear
non-classical
optical
phenomena.
Since
emergence
features
is
directly
linked
to
properties,
detailed
simulations
characteristics
are
required
development
low-noise
optoelectronic
sources.
Our
semiclassical
framework
based
on
Lindblad
equation
electron
dynamics,
coupled
with
Maxwell’s
equations
propagation
laser
waveguide.
Fluctuations
arising
from
interactions
field
system
their
reservoirs
treated
within
Langevin
theory.
Here,
fluctuations
included
by
adding
equations.
implementation
mbsolve
dynamic
publicly
available.
Language: Английский
Theory of Hybrid Microwave–Photonic Quantum Devices
Laser & Photonics Review,
Journal Year:
2023,
Volume and Issue:
17(12)
Published: Aug. 25, 2023
Abstract
The
Maxwell–Lindblad
transmission
line
(MLT)
equations
are
introduced
as
a
model
for
hybrid
photonic
and
microwave‐electronic
quantum
devices.
concept
has
long
enabled
high‐bandwidth
photodetectors
modulators
by
using
waveguide
structures
supporting
microwave–optical
co‐propagation.
Extending
this
technique
to
quantum‐engineered
lasers
provides
route
greatly
improved
short‐pulse
frequency
comb
operation,
impressively
demonstrated
cascade
lasers.
Even
more,
the
self‐organized
formation
of
coupled
microwave
optical
oscillation
patterns
recently
photonics‐based
ultralow‐noise
generation.
MLT
suitable
theoretical
description
devices
combining
propagation
with
Lindblad‐type
approach
active
region
dynamics.
A
stable
numerical
scheme
is
presented,
enabling
realistic
device
simulations
in
excellent
agreement
experimental
data.
Based
on
results
analytical
considerations,
it
that
functionality
investigated
does
not
only
rely
local
coupling
effects,
but
rather
benefits
from
microwave‐optical
co‐propagation,
settling
an
ongoing
debate.
provide
basis
systematic
development
extension
other
based
on,
example,
dot
or
interband
structures,
well
simplified
models
providing
additional
intuitive
insight.
Language: Английский
Multi-Domain Modeling of Free-Running Harmonic Frequency Comb Formation in Terahertz Quantum Cascade Lasers
IEEE photonics journal,
Journal Year:
2024,
Volume and Issue:
16(2), P. 1 - 11
Published: Feb. 27, 2024
Optical
frequency
comb
(OFC)
emission
in
quantum
cascade
lasers
(QCLs)
is
highly
attractive
for
applications
metrology
and
sensing.
Recently,
coherent
OFC
mode-locking
with
large
intermodal
spacing
was
demonstrated
QCLs.
These
self-starting
harmonic
combs
(HFCs)
show
phase-stable
operation
promise
interesting
perspectives
towards
optical
or
even
communication.
Here,
we
present
a
detailed
multi-domain
modeling
approach
the
numerical
study
of
Our
theoretical
characterization
divided
into
stationary
carrier
transport
simulations,
based
on
ensemble
Monte
Carlo
method,
dynamical
simulations
light-matter
interaction,
multi-level
Maxwell-density
matrix
equations.
We
investigate
influence
chosen
eigenstate
basis
gain
spectrum
self-consistent
simulation
results
stable
HFC
double
metal
terahertz
QCL.
In
our
studied
QCL
medium
shows
different
bias
waveguide
configurations,
resulting
mode
up
to
twelve
times
cavity
round
trip
frequency.
Furthermore,
characterize
spectral
time
evolution
formation
process,
yielding
spontaneous
build-up
dense
multimode
state
which
gradually
transferred
broad
clear
state.
Language: Английский
Efficient strain-modified improved nonparabolic-band energy dispersion model that considers the effect of conduction band nonparabolicity in mid-infrared quantum cascade lasers
Optics Express,
Journal Year:
2023,
Volume and Issue:
31(19), P. 31267 - 31267
Published: Sept. 1, 2023
Intersubband
polar-optical-phonon
(POP)
scattering
plays
an
important
role
in
determining
the
population
inversion
and
optical
gain
of
mid-infrared
(mid-IR)
quantum
cascade
lasers
(QCLs).
In
particular,
nonparabolicity
conduction
band
(CB)
significantly
affects
energy
dispersion
relation
intersubband
POP
time.
However,
currently
used
parabolic-band
(PB)
nonparabolic-band
(NPB)
models
are
not
appropriate
for
mid-IR
QCLs
because
they
unsuitable
high
electron
wave
vectors
do
consider
effect
applied
strain
on
CB.
The
eight-band
k·p
method
can
provide
a
relatively
accurate
nonparabolic
but
has
disadvantages
computational
complexity
spurious
solutions
to
be
discarded.
Consequently,
we
propose
strain-modified
improved
(INPB)
model
that
no
solution
acceptable
accuracy,
compared
method.
To
demonstrate
accuracy
efficiency
our
proposed
INPB
with
those
PB,
NPB,
models,
calculate
relations
times
strain-compensated
QCL
lasing
wavelength
3.58
µm.
Calculation
results
reveal
is
almost
as
model;
however,
it
enables
much
faster
calculations
free
from
solutions.
Language: Английский
Multi-Domain Modeling of Free-Running Harmonic Frequency Comb Formation in Terahertz Quantum Cascade Lasers
Published: Nov. 27, 2023
<p>In
our
manuscript,
we
present
a
detailed
multi-domain
modeling
approach
for
the
numerical
study
of
free-running
harmonic
frequency
comb
(HFC)
formation
in
terahertz
quantum
cascade
lasers
(QCLs).
We
investigate
influence
chosen
eigenstate
basis
on
gain
spectrum
and
self-consistent
simulation
results
stable
HFC
operation
double
metal
QCL.<br>
In
simulations,
studied
QCL
medium
shows
self-starting
mode-locking
different
bias
waveguide
configurations,
resulting
mode
spacing
up
to
eight
times
cavity
round
trip
frequency.
Furthermore,
characterize
spectral
time
evolution
coherent
process,
yielding
spontaneous
build-up
dense
multimode
state
which
is
gradually
transferred
into
broad
clear
state.</p>
Language: Английский