March 17, 2014 – Applied Physics letters
First demonstration of optical real-time data compression
demonstrate the first instrument for compressing the time-bandwidth product of analog signals in
real-time. By performing self-adaptive stretch, this technology enables digitizers to capture waveforms
beyond their bandwidth with digital data size being reduced at the same time. The compression is
lossless and is achieved through a transformation of the signal's complex field, performed in the
analog domain prior to
proof of concept experiments, we compress the modulation bandwidth of an optical signal by 500 times.
At the same time, we reduce its modulation time-bandwidth product (i.e., the record length) by 2.73
times while achieving 16?dB power efficiency improvement in comparison to the case of using
conventional dispersive Fourier transform. Dispersive data compression addresses the big data problem
in real-time instruments and in optical communications.
New discovery is rooted in physics and the arts
New Compression Method Reduces Big Data Bottleneck
December 18, 2013
Big Data refers generally to vast
amounts of information collected by networked devices and systems. In this domain, data capture is
technologically simple and the challenge lies in the post-capture analytics and transmission. Big Data
is also prominent in other domains where the capture of data is challenging as well, such as in the
medical sciences, telecom and basic research in the sciences. In these areas, communication signals and
scientific phenomena of interest tend to occur on time scales and at throughput levels that are too
fast to be sampled and digitized in real time.
In other words, the Big Data
problem is not just limited to analytics; it also includes data capture, storage, and transmission.
Anamorphic Stretch Transform (AST) is a new mathematical transform
that offers a solution for Big
Data bottleneck, it slows down ultrafast signal so it can be captured with a slower instrument and at
the same time it compresses the volume of the resulting data. It does so by reducing the
length-bandwidth product. AST can operate on both analog and all-digital data such as on images where
it outperforms JPEG and other standard compression techniques. AST is a non-iterative algorithm and
does not need any feature detection, feedback.
OPN February 2014 Article
Paper (time domain)
2013-09-25 -- Nature Photonics
Congratulations to Eric Diebold and Brandon Buckley whose work was published in Nature Photonics!
Their work was also featured in Nature Methods
Fluorescence imaging is the most widely used method for unveiling the molecular composition of
biological specimens. However, the weak optical emission of fluorescent probes and the trade-off
between imaging speed and sensitivity are problematic for acquiring blur-free images of fast phenomena,
such as sub-millisecond biochemical dynamics in live cells and tissues, and cells flowing at high
speed. Here, we report a technique that achieves real-time pixel readout rates that are one order of
magnitude faster than a modern electron multiplier charge-coupled devicethe gold standard in highspeed
fluorescence imaging technology. Termed fluorescence imaging using radiofrequency-tagged emission
(FIRE), this approach maps the image into the radiofrequency spectrum using the beating of digitally
synthesized optical fields. We demonstrate diffraction-limited confocal fluorescence imaging of
stationary cells at a frame rate of 4.4 kHz, and fluorescence microscopy in flow at a velocity of 1
m/s, corresponding to a throughput of approximately 50,000 cells per second.
2013-08-15 -- Wiley
Congratulations to Peter DeVore and David Borlaug whose work was selected for the rear cover of
Physica Status Solidi Rapid Research Letters! Modulation instability is a universal nonlinear process
wherein a weak perturbation grows on an otherwise quiet background. Inspired by recent work on
stimulating modulation instability to tame optical rogues waves, DeVore, Borlaug, and Jalali stimulate
it with the weak sidebands of an electrooptically modulated carrier. In this process, the sidebands are
boosted at the expense of the carrier, which enables low-voltage, high bandwidth modulation, one of the
most pressing needs in optical communications. In the cover figure, we see that a traditional optical
link weakly transfers high-frequency radio frequency waves, but the fortuitous increase of modulation
instability gain with frequency allows transfer of the full bandwidth.
|2013-08-13 -- Interactive Steam Calculator Goes Live
Serial time-encoded amplified imaging/microscopy (STEAM) is a fast real-time optical imaging
method that provides ~10 MHz frame rate, ~100 ps shutter speed, and ~30 dB ( 1000) optical image gain.
As of today, STEAM holds world records for shutter speed and frame rate in continuous real-time
imaging. STEAM employs the photonic time stretch along with optical image amplification to circumvent
the fundamental trade-off between sensitivity and speed that affects virtually all optical imaging and
sensing systems. With this calculator, you will be able to determine spatial and temporal resolution of
1D STEAM System. Please click the schematic or link to explore further.
2013-07-18 -- IOP Science
Rogue events are statistically rare but carry a huge impact. Occurring in everyday contexts such
as finance, network traffic, ocean waves and elsewhere. Launching intense pulses into silicon
waveguides results in supercontinuum generation, strong nonlinear optical broadening due to a host of
complex interactions. This complex mixing of frequencies occasionally results in especially strong
broadening, yielding heavy-tailed distribution from what was once Gaussian noise. By stimulating the
initial conditions with a well-chosen seed, the broadening can be controlled and stabilized.
2013-06-29 -- Congratulations
to David Borlaug for being awarded a PhD Fellowship from Sandia National Labs. The fellowship comes
with full time funding and the opportunity to earn significantly more through summer internships.
Sandia is aware of our work and is interested in using the fellowship as a platform to build a long
term relationship with our lab on a variety of topics. We are proud of David and wish him continued
success going forward.
2013-05-24 -- Congratulations to
our alumnus and now Professor at the College of Optics (CREOL) in University of Central Florida, Sasan
Fathpour, for winning the prestigious Office of Naval Research Young Investigator Award. Sasan is known
for the first demonstration of nonlinear photovoltaic phenomenon in optics and for energy harvesting in
silicon photonics, accomplishments he made in our laboratory. The ONR award recognizes his latest
innovative work in the area hybrid silicon-LiNbO3 integrated devices.
2013-05-07 -- Congratulations to
Eric Diebold for winning the UCLA Chancellors Postdoctoral Award. Eric won this award for his
pioneering contribution to fluorescence microscopy and for the landmark demonstration of the worlds
fastest fluorescent camera.
Nature photonics (January
2013): Dispersive Fourier transformation is an emerging measurement technique that overcomes the speed
limitations of traditional optical instruments and enables fast continuous single-shot measurements in
optical sensing, spectroscopy and imaging. Using chromatic dispersion, dispersive Fourier
transformation maps the spectrum of an optical pulse to a temporal waveform whose intensity mimics the
spectrum, thus allowing a single-pixel photodetector to capture the spectrum at a scan rate
significantly beyond what is possible with conventional space-domain spectrometers. Over the past
decade, this method has brought us a new class of real-time instruments the permit the capture of rare
events such as optical rogue waves and rare cancer cells in blood, which would otherwise be missed
using conventional instruments.
Nature photonics (January
2013): Stochastically driven nonlinear processes are responsible for spontaneous pattern formation and
instabilities in numerous natural and artificial systems, including well-known examples such as sand
ripples, cloud formations, water waves, animal pigmentation and heart rhythms. Technologically, a type
of such self-amplification drives free-electron lasers and optical supercontinuum sources whose
radiation qualities, however, suffer from the stochastic origins. Through time-resolved observations,
we identify intrinsic properties of these fluctuations that are hidden in ensemble measurements. We
acquire single-shot spectra of modulation instability produced by laser pulses in glass fibre at
megahertz real-time capture rates. The temporally confined nature of the gain physically limits the
number of amplified modes, which form an antibunched arrangement as identified from a statistical
analysis of the data. These dynamics provide an example of pattern competition and interaction in
confined nonlinear systems.
Our work about
the high-throughput single-microparticle imaging flow analyzer has been published in
PNAS online and
UCLA Newsroom and
Highlights. The technology can take a picture of every single cell in a microfluidic channel with a
record high throughput of 100,000 cells/s and perform non-stop image-based cell classification in real
time. It holds promise for a broad range of applications such as high-throughput screening, cancer
detection, and stem cell research. The work has been highlighted in
TIME Magazine and
Nora Brackbill received
Science Foundation Graduate Fellowship and will attend Stanford University Ph.D. program in
researcher Rebecca Brown got admitted to and will attend medical school in July 2013.
Postdoctoral scholar Keisuke
Goda (2007-2012) appointed Full Professor at University of Tokyo.
Jalali received the
Kressel Award from the IEEE photonics society.
Bahram Jalali received The 2012 Distinguished Engineering Achievement Award from The Engineers'
Ali Fard has won
the 2011-2012 Electrical Engineering Department's Distinguished Ph.D. Dissertation Award in
Physical & Wave Electronics.
Kam Yan Hon's paper
Nonlinear Optical Coefficients of Si, Ge, and Si(1-x)Ge(x) in the midwave and longwave
infrared" has been selected to be on the cover of Journal of Applied Physics. Congratulations!
Using a combination of semiconductor theory and experimental results from the scientific
literature, we have compiled and plotted the key third-order nonlinear optical coefficients of bulk
crystalline Si and Ge as a function of wavelength (1.5-6.7 um for Si and 2.0-14.7 um for Ge).
Ali Fard wins
SPIE Scholarship. This award recognizes his
academic and research excellence in the field of optics and photonics. Congratulations!
Keisuke Goda wins
Welcome Fund Career Award at the Scientific Interface! The purpose of this award is to bridge
advanced postdoctoral training and the first three years of faculty service. Congratulations!