This
study
presents
a
new
method
for
detecting
hydrogen
cyanide
(HCN)
using
custom
quartz
tuning
fork
(QTF)
combined
with
dual-tube
acoustic
micro-resonator
(AmR)
improved
photoacoustic
gas
sensing.
The
AmR's
design
was
optimized
through
theoretical
simulations
and
experiments,
resulting
in
robust
on-beam
Quartz-Enhanced
Photoacoustic
Spectroscopy
(QEPAS)
setup.
An
Erbium-Doped
Fiber
Amplifier
(EDFA)
integrated
to
enhance
laser
power
by
286
times,
while
transformer-based
U-shaped
neural
network
served
as
machine
learning
filter
refine
signals
reduce
background
noise.
approach
achieved
low
HCN
detection
limit
of
0.89
parts
per
billion
(ppb)
rapid
1-second
response
time,
marking
significant
advancement
optical
Validation
tests
confirmed
the
system's
effectiveness
real-time,
high-sensitivity
environmental
monitoring
industrial
safety
applications,
showcasing
notable
improvements
QEPAS
technology
suggesting
further
potential
portable
systems.
Optics Letters,
Год журнала:
2024,
Номер
49(11), С. 3206 - 3206
Опубликована: Янв. 31, 2024
In
this
work,
we
developed
off-plane
quartz-enhanced
photoacoustic
spectroscopy
(OP-QEPAS).
the
OP-QEPAS
light
beam
went
neither
through
prong
spacing
of
quartz
tuning
fork
(QTF)
nor
in
QTF
plane.
The
is
parallel
with
an
optimal
distance,
resulting
low
background
noise.
A
radial-cavity
(RC)
resonator
was
coupled
to
enhance
signal
by
radial
resonance
mode.
By
offsetting
both
and
laser
position
from
central
axis,
effect
acoustic
prevent
noise
generated
direct
irradiation
QTF.
Compared
IP-QEPAS
based
on
a
bare
QTF,
RC
showed
>10×
signal-to-noise
ratio
(SNR)
enhancement.
system
has
great
advantages
use
emitting
devices
(LEDs),
long-wavelength
sources
such
as
mid-infrared
quantum
cascade
lasers,
terahertz
sources.
When
employing
LED
excitation
source,
level
suppressed
∼2
orders
magnitude.
Furthermore,
longitudinal
modes
can
be
combined
further
improve
sensor
performance.
Sensors,
Год журнала:
2024,
Номер
24(20), С. 6577 - 6577
Опубликована: Окт. 12, 2024
The
rapid
growth
of
industry
and
the
global
drive
for
modernization
have
led
to
an
increase
in
gas
emissions,
which
present
significant
environmental
health
risks.
As
a
result,
there
is
growing
need
precise
sensitive
gas-monitoring
technologies.
This
review
delves
into
progress
made
regarding
photoacoustic
sensors,
with
specific
focus
on
vital
components
acoustic
cells
detectors.
highlights
spectroscopy
(PAS)
as
optical
detection
technique,
lauding
its
high
sensitivity,
selectivity,
capability
detect
wide
range
gaseous
species.
principles
sensors
are
outlined,
emphasizing
use
modulated
light
absorption
generate
heat
subsequently
pressure
pressure.
Additionally,
this
provides
overview
recent
advancements
sensor
while
also
discussing
applications,
challenges,
limitations
these
sensors.
It
includes
comparative
analysis
other
types
along
potential
future
research
directions
opportunities.
main
aim
advance
understanding
development
technology.
Sensors,
Год журнала:
2025,
Номер
25(7), С. 2099 - 2099
Опубликована: Март 27, 2025
A
carbon
dioxide
(CO2)
sensor
based
on
light-induced
thermoelastic
spectroscopy
(LITES)
using
a
2
μm
diode
laser
and
self-designed
low-frequency
trapezoidal-head
QTF
is
reported
for
the
first
time
in
this
invited
paper.
The
with
low
resonant
frequency
of
9464.18
Hz
high
quality
factor
(Q)
12,133.56
can
significantly
increase
accumulation
signal
level
CO2-LITES
sensor.
continuous-wave
(CW)
distributed-feedback
(DFB)
used
as
light
source,
strongest
absorption
line
CO2
located
at
2004.01
nm
chosen.
comparison
between
standard
commercial
32.768
kHz
performed.
experimental
results
show
that
has
an
excellent
linear
response
to
concentration,
its
minimum
detection
limit
(MDL)
reach
46.08
ppm
(parts
per
million).
When
average
increased
100
s
Allan
variance
analysis,
MDL
be
improved
3.59
ppm.
Compared
16.85
QTF,
performance
by
4.7
times,
demonstrating
superiority
QTF.
Light Science & Applications,
Год журнала:
2025,
Номер
14(1)
Опубликована: Апрель 30, 2025
Highly
sensitive
gas
detection
plays
a
crucial
role
in
advanced
scientific
and
technological
fields.
This
paper
presents
parts-per-quadrillion
(ppq)
level
ultra-highly
light-induced
thermoelectric
spectroscopy
(LITES)
sensor
for
the
first
time.
The
artificial
fish
swarm
algorithm
auto-designed
multi-pass
cell
(MPC)
with
double
helix
pattern,
polymer
modified
round-head
quartz
tuning
fork
(QTF)
low-resonant
frequency
(f0)
were
adopted
to
improve
absorption
QTF's
ability.
obtained
MPC,
long
optical
path
length
(OPL)
of
25.8
m
small
volume
165.8
ml,
is
beneficial
increasing
while
keeping
compact.
novel
QTF
was
structurally
optimized
obtain
low
f0
(~9.5
kHz)
by
polydimethylsiloxane
(PDMS)
reduce
heat
diffusion
enhance
vibration
amplitude.
A
strong
line
carbon
monoxide
(CO)
located
mid-infrared
region
(4.59
μm)
chosen
as
target
line.
signal-to-noise
ratio
(SNR)
CO-LITES
based
on
improved
10.59
times,
reaching
highest
when
compared
commercial
QTF.
corresponding
minimum
limit
(MDL)
calculated
be
23
ppt.
When
integration
time
system
increased
500
s,
MDL
could
920.7
ppq.
Compared
reported
techniques
CO
detection,
LITES
this
study
offers
an
excellent
result
terms
sensitivity.
IEEE Sensors Journal,
Год журнала:
2024,
Номер
24(7), С. 9888 - 9893
Опубликована: Фев. 14, 2024
Light-induced
thermoelastic
spectroscopy
(LITES),
boasting
an
extended
effective
optical
path
length,
stands
as
a
potent
approach
for
trace
gas
detection.
The
indispensable
factor
heightened
measurement
sensitivity
lies
in
the
quartz
tuning
fork
(QTF)
probe,
possessing
robust
conversion
efficiency.
In
this
study,
we
introduce
novel
laser
micromachining
technique
fabricating
sensitive
miniature
QTFs
(mQTFs)
tailored
to
suit
LITES
applications.
This
innovation
effectively
addresses
issues
of
subpar
and
elevated
response
threshold
commonly
observed
commercial
QTFs.
As
proof
concept,
demonstrate
its
capabilities
through
CO2.
Capitalizing
on
utilization
mQTFs,
sensing
was
increased
by
impressive
~5,
outperforming
conventional
QTF-LITES
approach.
minimum
detection
limits
(MDLs)
CO2
are
also
notably
improved,
measuring
351.34
ppm
mQTF
968.29
standard
QTF.
cost-effective
technological
advancement
paves
way
development
highly
responsive
systems.
