arXiv (Cornell University),
Journal Year:
2023,
Volume and Issue:
unknown
Published: Jan. 1, 2023
Optical
phase
conjugation
(OPC)
is
a
nonlinear
technique
used
for
counteracting
wavefront
distortions,
with
various
applications
ranging
from
imaging
to
beam
focusing.
Here,
we
present
the
design
of
diffractive
processor
approximate
all-optical
operation
input
fields
aberrations.
Leveraging
deep
learning,
set
passive
layers
was
optimized
all-optically
process
an
arbitrary
phase-aberrated
coherent
field
aperture,
producing
output
distribution
that
conjugate
wave.
We
experimentally
validated
efficacy
this
by
3D
fabricating
trained
using
learning
and
performing
OPC
on
distortions
never
seen
during
its
training.
Employing
terahertz
radiation,
our
physical
successfully
performed
task
through
shallow
spatially-engineered
volume
axially
spans
tens
wavelengths.
In
addition
transmissive
configuration,
also
created
phase-conjugate
mirror
combining
learning-optimized
standard
mirror.
Given
compact,
scalable
nature,
can
be
diverse
OPC-related
applications,
e.g.,
turbidity
suppression
aberration
correction,
adaptable
different
parts
electromagnetic
spectrum,
especially
those
where
cost-effective
engineering
solutions
do
not
exist.
Abstract
Many
exciting
terahertz
imaging
applications,
such
as
non-destructive
evaluation,
biomedical
diagnosis,
and
security
screening,
have
been
historically
limited
in
practical
usage
due
to
the
raster-scanning
requirement
of
systems,
which
impose
very
low
speeds.
However,
recent
advancements
systems
greatly
increased
throughput
brought
promising
potential
radiation
from
research
laboratories
closer
real-world
applications.
Here,
we
review
development
technologies
both
hardware
computational
perspectives.
We
introduce
compare
different
types
enabling
frequency-domain
time-domain
using
various
thermal,
photon,
field
image
sensor
arrays.
discuss
how
algorithms
provide
opportunities
for
capturing
time-of-flight,
spectroscopic,
phase,
intensity
data
at
high
throughputs.
Furthermore,
new
prospects
challenges
future
high-throughput
are
briefly
introduced.
Abstract
The
all‐optical
diffractive
deep
neural
networks
(D
2
NNs)
framework
as
a
hardware
platform
is
demonstrated
to
implement
various
advanced
functional
meta‐devices
with
high
parallelism
and
processing
speed.
However,
the
design
methodology
merging
trainable
polarization
modulation
neurons
into
D
NNs,
which
potentially
possess
higher
integration
more
task‐loading
capacity,
not
yet
fully
explored.
Here,
matrix
(M‐D
are
proposed
deploy
polarization‐sensitive
Jones
metasurfaces
multiplexing
perform
sophisticated
inference
tasks
well
inverse
designs
for
meta‐devices.
Three
functionalities
implemented
by
M‐D
that
is,
task‐capacity
classification,
non‐interleaved
high‐efficiency
eight‐channel
regulation,
custom‐polarization
information
cryptographic
multiplexing.
NNs
provide
new
strategy
merge
electromagnetic
optical
field
modulators
metasurfaces,
may
drive
evolution
of
toward
multi‐task
devices.
Nature Communications,
Journal Year:
2024,
Volume and Issue:
15(1)
Published: Feb. 20, 2024
Abstract
Structured
optical
materials
create
new
computing
paradigms
using
photons,
with
transformative
impact
on
various
fields,
including
machine
learning,
computer
vision,
imaging,
telecommunications,
and
sensing.
This
Perspective
sheds
light
the
potential
of
free-space
systems
based
engineered
surfaces
for
advancing
computing.
Manipulating
in
unprecedented
ways,
emerging
structured
enable
all-optical
implementation
mathematical
functions
learning
tasks.
Diffractive
networks,
particular,
bring
deep-learning
principles
into
design
operation
to
functionalities.
Metasurfaces
consisting
deeply
subwavelength
units
are
achieving
exotic
responses
that
provide
independent
control
over
different
properties
can
major
advances
computational
throughput
data-transfer
bandwidth
processors.
Unlike
integrated
photonics-based
optoelectronic
demand
preprocessed
inputs,
processors
have
direct
access
all
degrees
freedom
carry
information
about
an
input
scene/object
without
needing
digital
recovery
or
preprocessing
information.
To
realize
full
architectures,
diffractive
metasurfaces
need
advance
symbiotically
co-evolve
their
designs,
3D
fabrication/integration,
cascadability,
accuracy
serve
needs
next-generation
computing,
telecommunication
technologies.
Abstract
Image
denoising,
one
of
the
essential
inverse
problems,
targets
to
remove
noise/artifacts
from
input
images.
In
general,
digital
image
denoising
algorithms,
executed
on
computers,
present
latency
due
several
iterations
implemented
in,
e.g.,
graphics
processing
units
(GPUs).
While
deep
learning-enabled
methods
can
operate
non-iteratively,
they
also
introduce
and
impose
a
significant
computational
burden,
leading
increased
power
consumption.
Here,
we
an
analog
diffractive
denoiser
all-optically
non-iteratively
clean
various
forms
noise
artifacts
images
–
at
speed
light
propagation
within
thin
visual
processor
that
axially
spans
<250
×
λ,
where
λ
is
wavelength
light.
This
all-optical
comprises
passive
transmissive
layers
optimized
using
learning
physically
scatter
optical
modes
represent
features,
causing
them
miss
output
Field-of-View
(FoV)
while
retaining
object
features
interest.
Our
results
show
these
denoisers
efficiently
salt
pepper
rendering-related
spatial
phase
or
intensity
achieving
efficiency
~30–40%.
We
experimentally
demonstrated
effectiveness
this
architecture
3D-printed
operating
terahertz
spectrum.
Owing
their
speed,
power-efficiency,
minimal
overhead,
be
transformative
for
display
projection
systems,
including,
holographic
displays.
Advanced Materials,
Journal Year:
2023,
Volume and Issue:
35(31)
Published: April 26, 2023
Abstract
Diffractive
optical
networks
provide
rich
opportunities
for
visual
computing
tasks.
Here,
data‐class‐specific
transformations
that
are
all‐optically
performed
between
the
input
and
output
fields‐of‐view
(FOVs)
of
a
diffractive
network
presented.
The
information
objects
is
encoded
into
amplitude
(
A
),
phase
P
or
intensity
I
)
field
at
input,
which
processed
by
network.
At
output,
an
image
sensor‐array
directly
measures
transformed
patterns,
encrypted
using
transformation
matrices
preassigned
to
different
data
classes,
i.e.,
separate
matrix
each
class.
original
images
can
be
recovered
applying
correct
decryption
key
(the
inverse
transformation)
corresponding
matching
class,
while
any
other
will
lead
loss
information.
All‐optical
class‐specific
covering
→
,
various
datasets
numerically
demonstrated.
feasibility
this
framework
also
experimentally
validated
fabricating
successfully
tested
parts
electromagnetic
spectrum,
1550
nm
0.75
mm
wavelengths.
Data‐class‐specific
all‐optical
fast
energy‐efficient
method
encryption,
enhancing
security
privacy.
Abstract
Diffractive
deep
neural
networks
(D
2
NNs)
are
composed
of
successive
transmissive
layers
optimized
using
supervised
learning
to
all-optically
implement
various
computational
tasks
between
an
input
and
output
field-of-view.
Here,
we
present
a
pyramid-structured
diffractive
optical
network
design
(which
term
P-D
NN),
specifically
for
unidirectional
image
magnification
demagnification.
In
this
design,
the
pyramidally
scaled
in
alignment
with
direction
or
This
NN
creates
high-fidelity
magnified
demagnified
images
only
one
direction,
while
inhibiting
formation
opposite
direction—achieving
desired
imaging
operation
much
smaller
number
degrees
freedom
within
processor
volume.
Furthermore,
maintains
its
magnification/demagnification
functionality
across
large
band
illumination
wavelengths
despite
being
trained
single
wavelength.
We
also
designed
wavelength-multiplexed
NN,
where
magnifier
demagnifier
operate
simultaneously
directions,
at
two
distinct
wavelengths.
demonstrate
that
by
cascading
multiple
modules,
can
achieve
higher
factors.
The
efficacy
architecture
was
validated
experimentally
terahertz
illumination,
successfully
matching
our
numerical
simulations.
offers
physics-inspired
strategy
designing
task-specific
visual
processors.
Advanced Intelligent Systems,
Journal Year:
2023,
Volume and Issue:
5(11)
Published: Aug. 25, 2023
As
a
label‐free
imaging
technique,
quantitative
phase
(QPI)
provides
optical
path
length
information
of
transparent
specimens
for
various
applications
in
biology,
materials
science,
and
engineering.
Multispectral
QPI
measures
across
multiple
spectral
bands,
permitting
the
examination
wavelength‐specific
dispersion
characteristics
samples.
Herein,
design
diffractive
processor
is
presented
that
can
all‐optically
perform
multispectral
phase‐only
objects
within
snapshot.
The
utilizes
spatially
engineered
layers,
optimized
through
deep
learning,
to
encode
profile
input
object
at
predetermined
set
wavelengths
into
spatial
intensity
variations
output
plane,
allowing
using
monochrome
focal
plane
array.
Through
numerical
simulations,
processors
are
demonstrated
simultaneously
9
16
target
bands
visible
spectrum.
generalization
these
designs
validated
tests
on
unseen
objects,
including
thin
Pap
smear
images.
Due
its
all‐optical
processing
capability
passive
dielectric
materials,
this
offers
compact
power‐efficient
solution
high‐throughput
microscopy
spectroscopy.
Abstract
Nonlinear
encoding
of
optical
information
can
be
achieved
using
various
forms
data
representation.
Here,
we
analyze
the
performances
different
nonlinear
strategies
that
employed
in
diffractive
processors
based
on
linear
materials
and
shed
light
their
utility
performance
gaps
compared
to
state-of-the-art
digital
deep
neural
networks.
For
a
comprehensive
evaluation,
used
datasets
compare
statistical
inference
simpler-to-implement
involve,
e.g.,
phase
encoding,
against
repetition-based
strategies.
We
show
repetition
within
volume
(e.g.,
through
an
cavity
or
cascaded
introduction
input
data)
causes
loss
universal
transformation
capability
processor.
Therefore,
blocks
cannot
provide
analogs
fully
connected
convolutional
layers
commonly
However,
they
still
effectively
trained
for
specific
tasks
achieve
enhanced
accuracy,
benefiting
from
information.
Our
results
also
reveal
without
provides
simpler
strategy
with
comparable
accuracy
processors.
analyses
conclusions
would
broad
interest
explore
push-pull
relationship
between
material-based
systems
visual