Science Bulletin,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 1, 2025
Bound
states
in
the
continuum
(BICs)
are
notable
photonics
for
their
infinite
Q
factors.
Perturbed
BICs,
or
quasi-BICs
(QBICs),
have
finite
but
ultra-high
factors,
enabling
external
coupling.
So
far,
most
studies
focused
on
momentum-space
properties
of
BICs
and
QBICs,
with
few
discussions
real
space.
Here,
we
experimentally
demonstrate
that
QBICs
can
induce
abrupt
lateral
beam
shifts.
By
applying
Brillouin
zone
folding
to
a
compound
grating
waveguide,
form
QBIC
band
where
all
become
QBICs.
When
excited
at
specific
incident
angles,
these
produce
sudden
shifts,
rapidly
disappearing
as
frequencies
deviate
from
band.
Using
terahertz
imaging,
capture
shifts
different
characterizing
This
work
offers
alternative
insights
into
behaviors
supports
development
advanced
sensors
wavelength
division
(de)
multiplexers.
Nano Letters,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Nov. 6, 2024
Dielectric
metasurface
supported
symmetry-protected
bound
states
in
the
continuum
(SP-BIC)
provide
an
important
platform
for
enhancing
light-matter
interactions.
However,
conversion
of
SP-BIC
into
quasi-BIC
(QBICs)
through
symmetry
breaking
is
often
accompanied
by
a
shift
resonance
wavelength.
In
this
work,
we
present
generalized
viewpoint
aimed
at
achieving
wavelength
stability
QBICs
and
area
compensation
(SBAC).
Three
SBAC
schemes
propose
are
equal
proportional
along
both
Nano Letters,
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 11, 2025
Photonic
quasi-bound
states
in
the
continuum
(quasi-BICs)
provide
an
excellent
platform
for
strong
light-matter
interactions
nanophotonics.
In
this
work,
we
numerically
and
experimentally
demonstrate
that
Si
nanorod
dimer
metasurface
offers
a
new
paradigm
realizing
multiple
wavelength-stabilized
quality-factor-tunable
quasi-BICs,
through
unique
symmetry
breaking
method
does
not
alter
volume.
A
pronounced
electromagnetically
induced
transparency
(EIT)
effect,
exhibiting
group
time
delay
of
6.7
ps,
coupling
accompanied
by
characteristic
anticrossing
Rabi
splitting
are
realized
based
on
hybridization
between
bright
mode
neighboring
quasi-BIC
within
multiresonant
metasurface.
Intriguingly,
sharp
window,
with
tunable
bandwidth
but
stable
wavelength,
is
achieved.
All
numerical
results
validated
experimental
demonstration.
Our
findings
recipe
wavelength-stabilized,
quasi-BICs
EIT-like
effect.
would
find
utility
slow
light,
quantum
storage,
nonlinear
optics.
Nanomaterials,
Journal Year:
2025,
Volume and Issue:
15(7), P. 477 - 477
Published: March 21, 2025
Metasurfaces,
composed
of
engineered
nanoantennas,
enable
unprecedented
control
over
electromagnetic
waves
by
leveraging
multipolar
resonances
to
tailor
light–matter
interactions.
This
review
explores
key
physical
mechanisms
that
govern
their
optical
properties,
including
the
role
in
shaping
metasurface
responses,
emergence
bound
states
continuum
(BICs)
support
high-quality
factor
modes,
and
Purcell
effect,
which
enhances
spontaneous
emission
rates
at
nanoscale.
These
effects
collectively
underpin
design
advanced
photonic
devices
with
tailored
spectral,
angular,
polarization-dependent
properties.
discusses
recent
advances
metasurfaces
applications
based
on
them,
highlighting
research
employs
full-wave
numerical
simulations,
analytical
semi-analytic
techniques,
decomposition,
nanofabrication,
experimental
characterization
explore
interplay
resonances,
quasi-bound
states,
enhanced
A
particular
focus
is
given
metasurface-enhanced
photodetectors,
where
structured
nanoantennas
improve
light
absorption,
spectral
selectivity,
quantum
efficiency.
By
integrating
conventional
photodetector
architectures,
it
possible
enhance
responsivity,
engineer
photocarrier
generation
rates,
even
functionalities
such
as
polarization-sensitive
detection.
The
between
BICs,
provides
a
unified
framework
for
designing
next-generation
optoelectronic
devices.
consolidates
progress
these
areas,
emphasizing
potential
metasurface-based
approaches
high-performance
sensing,
imaging,
energy-harvesting
applications.
Nano Letters,
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 25, 2025
Achieving
ultrahigh
quality
factor
optical
resonances
is
crucial
for
advancing
low-threshold
lasers,
high-sensitivity
sensors,
and
nonlinear
photonics.
While
dielectric
metasurfaces
supporting
quasi-bound
states
in
the
continuum
(qBICs)
show
great
potential,
their
experimental
realization
has
been
challenging
due
to
difficulty
of
precisely
controlling
symmetry-breaking
at
nanoscale.
Here,
we
introduce
a
precision-controlled
symmetry-protected
qBIC
method
using
angular
perturbations
tune
asymmetry,
ensuring
both
high
precision
reproducibility
Q-factors.
In
contrast
traditional
SP-qBIC
excitation,
which
relies
on
uncontrolled
our
offers
more
accurate
consistent
control
by
tuning
instead
structural
variations.
Additionally,
approach
defines
lower
limit
achievable
Q-factors,
providing
reliable
bound.
The
demonstration
SP-qBICs
composite
nanoslit
achieves
record-breaking
Q-factor
1.1
×
105-the
highest
reported
date.
These
findings
offer
promising
platform
designing
ultrahigh-Q
resonators
next-generation
photonic-applications.
Optics Letters,
Journal Year:
2024,
Volume and Issue:
49(20), P. 5703 - 5703
Published: Oct. 2, 2024
High-Q
intrinsic
quasi-bound
states
in
the
continuum
(QBICs)
require
three-dimensional
(3D)
geometries
with
both
in-plane
and
out-of-plane
mirror
symmetry
breakings,
hindering
practical
implementations
due
to
complex
architectures.
Here
we
demonstrate
that
high-Q
QBICs
can
be
flexibly
controlled
by
using
engineered
2.5D
phase-change
metasurfaces
of
Ge
2
Sb
Te
5
(GST).
By
introducing
additional
perturbations
slant
angle
θ
azimuthal
φ
,
highly
efficient
circular
dichroism
(CD)
for
reflection
transmission
realized.
The
spinning-selected
magnetic
dipole
(MD)
is
responsible
chirality.
CD
robust
variation
structural
parameters,
its
Q-factor
resonance
location
tuned
through
phase
transition
GST.
