2013-09-30 -- Applied Optics
Congratulations to Mohammad H. Asghari whose work was published in Applied Optics. A general
method for compressing the modulation time–bandwidth product of analog signals is introduced. As one
of its applications, this physics-based signal grooming, performed in the analog domain, allows a
conventional digitizer to sample and digitize the analog signal with variable resolution. The net
result is that frequency components that were beyond the digitizer bandwidth can now be captured and,
at the same time, the total digital data size is reduced. This compression is lossless and is
achieved through a feature selective reshaping of the signal’s complex field, performed in the analog
domain prior to sampling. Our method is inspired by operation of Fovea centralis in the human eye and
by anamorphic transformation in visual arts. The proposed transform can also be performed in the
digital domain as a data compression algorithm to alleviate the storage and transmission bottlenecks
associated with “big data.”
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
pdf. 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
device—the 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
|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 Chancellor’s Postdoctoral Award. Eric won this award for his
pioneering contribution to fluorescence microscopy and for the landmark demonstration of the world’s
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
researcher 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.
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.
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!