on a substrate crystal of nonmagnetic strontium titanate using a method pulsed laser deposition developed many years ago for high-temperature superconductors and multicomponent materials by Prof Venkatesan,
The new perovskite film, with the formula Srxla1-xcro3,(x up to 0. 25), conducts electricity more effectively than the unmodified oxide and yet retains much of the transparency to visible light exhibited by the pure material.
light detectors, and several kinds of electronic devices that are by nature transparent to visible light. Of particular importance are new materials that conduct electricity by using missing electrons, otherwise known as"holes."
#New, ultrathin optical devices shape light in exotic ways Caltech engineers have created flat devices capable of manipulating light in ways that are very difficult
and cameras that can be mass-produced using the same photolithography techniques used to manufacture computer microchips."
or monochromatic light oscillates at all points in space with the same frequency but varying relative delays, or phases.
Manipulating the polarization of light is essential for the operation of advanced microscopes, cameras, and displays;
and phase of light,"says study first author Amir Arbabi, a senior researcher at Caltech."
"We can take any incoming light and shape its phase and polarization profiles arbitrarily and with very high efficiency."
a metasurface device could manipulate light in novel ways that are very hard and sometimes impossible to do using current setups.
when illuminated by a horizontally polarized beam of light, and a different image when illuminated by a vertically polarized beam."
"The two images will appear overlapped under illumination with light polarized at 45 degrees, "Faraon says.
and have applications in superresolution microscopy, laser cutting, and particle acceleration.""You generally would need a large optical setup,
Alivisatos and Ralph Nuzzo of the University of Illinois are the corresponding authors of a paper in ACS Photonics describing this research entitled Quantum dot Luminescent Concentrator Cavity Exhibiting 30-fold Concentration.
an LSC absorbs the light on a plate embedded with highly efficient light-emitters called lumophores that then re-emit the absorbed light at longer wavelengths, a process known as the Stokes shift.
This re-emitted light is directed to a micro-solar cell for conversion to electricity. Because the plate is much larger than the micro-solar cell,
With a sufficient concentration factor, only small amounts of expensive III-V photovoltaic materials are needed to collect light from an inexpensive luminescent waveguide.
imperfect light trapping within the waveguide, and reabsorption and scattering of propagating photons. We replaced the molecular dyes in previous LSC systems with core/shell nanoparticles composed of cadmium selenide (Cdse) cores
In their ACS Photonics paper, the collaborators express confidence that future LSC devices will achieve even higher concentration ratios through improvements to the luminescence quantum yield, waveguide geometry,
and conceal it from detection with visible light. Although this cloak is only microscopic in size,
The surface of the skin cloak was engineered meta to reroute reflected light waves so that the object was rendered invisible to optical detection
"This is the first time a 3d object of arbitrary shape has been cloaked from visible light, "said Xiang Zhang,
is the corresponding author of a paper describing this research in Science("An ultrathin invisibility skin cloak for visible light").
"It is the scattering of light-be infrared it visible , X-ray, etc.,-from its interaction with matter that enables us to detect
For the past ten years, Zhang and his research group have been pushing the boundaries of how light interacts with metamaterials,
"Creating a carpet cloak that works in air was so difficult we had embed to it in a dielectric prism that introduced an additional phase in the reflected light,
when red light struck an arbitrarily shaped 3d sample object measuring approximately 1, 300 square microns in area that was wrapped conformally in the gold nanoantenna skin cloak,
the light reflected off the surface of the skin cloak was identical to light reflected off a flat mirror,
and the phase of the scattered light so that the object remains perfectly hidden, "says co-lead author Zi Jing Wong, also a member of Zhang's research group.
The ability to manipulate the interactions between light and metamaterials offers tantalizing future prospects for technologies such as high resolution optical microscopes and superfast optical computers.
Invisibility skin cloaks on the microscopic scale might prove valuable for hiding the detailed layout of microelectronic components or for security encryption purposes.
By firing two time-delayed, ultrashort laser pulses at a helium atom, the researchers found that the distribution of momentum values for these intersecting electron waves can take the form of a two-armed vortex that resembles a spiral galaxy.
Though the spiral had been observed in waves of light, the team study is the first to produce the pattern with electrons.
Starace called the pattern an xcellent diagnostic toolfor characterizing electron-manipulating laser pulses which occur on such fast time scales that physicists have sought multiple ways to measure their durations and intensities.
Like all light, laser pulses feature electric fields that normally point in many directions. Polarizing a laser pulse aligns these fields along one direction,
while circularly polarizing a pulse aligns and then essentially rotates the fields around an axis. The team first pulse of circularly polarized light rotated in one direction,
with the second rotating the opposite way. These orientations dictate whether the resulting spiral pattern appears to swirl left or right
should help inform future investigations involving ultrafast laser physics. ttosecond science is still a new field,
#A thermal invisibility cloak actively redirects heat Light, sound, and now, heat--just as optical invisibility cloaks can bend
and diffract light to shield an object from sight, and specially fabricated acoustic metamaterials can hide an object from sound waves,
The new material, produced by grain boundary lithography, solves that problem, he said. In addition to Ren, other researchers on the project included Chuan Fei Guo and Ching-Wu"Paul"Chu, both from UH;
The grain boundary lithography involved a bilayer lift off metallization process, which included an indium oxide mask layer and a silicon oxide sacrificial layer and offers good control over the dimensions of the mesh structure.
an element used in incandescent light bulbs. As the sample was tilted 62 times the researchers were able to slowly assemble a 3-D model of 3, 769 atoms in the tip of the tungsten sample.
The researchers present their development in the journal Nature Photonics. Light determines the future of information and communication technology:
The change from crystalline to amorphous (storing data) and from amorphous to crystalline (erasing data) is initiated by ultrashort light pulses.
For reading out the data, weak light pulses are used. Permanent all-optical on-chip memories might considerably increase future performance of computers
#Pushing the limits of lensless imaging Using ultrafast beams of extreme ultraviolet light streaming at a 100,000 times a second, researchers from the Friedrich Schiller University Jena,
Not only did they make the highest resolution images ever achieved with this method at a given wavelength,
The researchers'wanted to improve on a lensless imaging technique called coherent diffraction imaging, which has been around since the 1980s.
scientists fire an X-ray or extreme ultraviolet laser at a target. The light scatters off, and some of those photons interfere with one another
creating a diffraction pattern. By analyzing that pattern, a computer then reconstructs the path those photons must have taken,
Over the last ten years, researchers have developed smaller, cheaper machines that pump out coherent, laser-like beams in the laboratory setting.
Zürch and a team of researchers from Jena University used a special, custom-built ultrafast laser that fires extreme ultraviolet photons a hundred times faster than conventional table-top machines.
With more photons, at a wavelength of 33 nanometers, the researchers were able to make an image with a resolution of 26 nanometers--almost the theoretical limit."
"Nobody has achieved such a high resolution with respect to the wavelength in the extreme ultraviolet before, "Zürch said.
The ultrafast laser also overcame another drawback of conventional table-top light sources: long exposure times.
Thanks to the new high-speed light source, Zürch and his colleagues have reduced the exposure time to only about a second--fast enough for real-time imaging.
#Pioneering research develops new way to capture light-for the computers of tomorrow The key breakthrough will allow large quantities of data to be stored directly on an integrated optical chip,
data transfer by means of light have long since become part of our everyday life, data on a computer are processed still
The team of scientists from Germany and England have made a key breakthrough by capturing light on an integrated chip,
The research is published in leading scientific journal, Nature Photonics("On-chip integratable all-photonic nonvolatile multilevel memory".
when a laser is directed at them, causing the capsule to burst and release its contents.
How hot the gold rods become depends on matching their size with the color of the laser light used.
and by employing different colored lasers. Because the capsules are 3d printed, they can be arranged within the gel in practically any design that can be created on a computer.
The ultrathin lens enables potential applications in on-chip nanophotonics and improves the conversion process of solar cells.
noninvasive 3d biomedical imaging photonic chips aerospace photonics micromachines laser tweezing the process of using lasers to trap tiny particles.
The rapid development in nano-optics and on-chip photonic systems has increased the demand for ultrathin flat lenses with three-dimensional subwavelength focusing capability the ability to see details of an object smaller than 200 nanometres.
Recent breakthroughs in nanophotonics have led to the development of a number of ultrathin flat lens concepts,
narrow operational bandwidth and time consuming manufacturing processes. ur lens concept has a 3d subwavelength capability that is 30 times more efficient, able to tightly focus broadband light
research leader in nanophotonics at Swinburne Centre for Microphotonics (CMP), Associate professor Baohua Jia, said. The researchers produced a film that is 300 times thinner than a sheet of paper by converting graphene oxide film to reduced graphene oxide through a photoreduction process. hese flexible graphene oxide lenses are mechanically robust
Phd candidate Xiaorui Zheng said. hey have the potential to revolutionise the next-generation integrated optical systems by making miniaturised and fully flexible photonics devices.
he newly demonstrated laser nano-patterning method in graphene oxides holds the key to fast processing and programming of high capacity information for big data sectors.
nanometer particles with the ability to absorb light and re-emit it with well-defined colors.
"For example, the elapsed time between light absorption and emission can be extended to be more than 100 times longer compared to conventional quantum dots,
#Ultrafast lasers offer 3-D micropatterning of biocompatible hydrogels Tufts University biomedical engineers are using low energy,
ultrafast laser technology to make high-resolution, 3-D structures in silk protein hydrogels. The laser-based micropatterning represents a new approach to customized engineering of tissue and biomedical implants.
The work is reported in a paper in PNAS Early Edition published September 15 online before print.
femtosecond laser to generate scalable, high-resolution 3-D voids within silk protein hydrogel, a soft,
Further, the exceptional clarity of the transparent silk gels enabled the laser's photons to be absorbed nearly 1 cm below the surface of the gel-more than 10 times deeper than with other materials
"Because the femtosecond laser pulses allow us to target specific regions without any damage to the immediate surroundings,
No radiation The new fusion process can take place in relatively small laser-fired fusion reactors fuelled by heavy hydrogen (deuterium.
"this tool should provide fast and reliable characterization of the different mechanisms cellular proteins use to bind to DNA strands information that could shed new light on the atomic-scale interactions within our cells
"Generally, most existing techniques to look at single-molecule movements such as optical tweezers have a resolution, at best,
They also looked at an indirect and much less studied effect of UV LIGHT. When the active ingredients of sunscreen absorb UV LIGHT a chemical change triggers the generation of oxygen-carrying molecules known as reactive oxygen species (ROS.
If a sunscreen agents penetrate the skin, this chemical change could cause cellular damage, and potentially facilitate skin cancer. ommercial chemical sunblock is protective against the direct hazards of ultraviolet damage of DNA,
"In this light, Lu's invention represents a major advancement for the mobile health industry.""After producing the cut-and-pasted patches,
which includes a photovoltaic cell using a high-quality semiconductor crystal similar to the ones for lasers
#Brightness-equalized quantum dots improve biological imaging Researchers at the University of Illinois at Urbana-Champaign have introduced a new class of light-emitting quantum dots (QDS) with tunable and equalized fluorescence brightness
"In this work, we have made two major advances--the ability to precisely control the brightness of light-emitting particles called quantum dots,
because the amount of light emitted from a single dye is unstable and often unpredictable.
These attributes obscure correlations between measured light intensity and concentrations of molecules,"stated Sung Jun Lim, a postdoctoral fellow and first author of the paper"
and improve color tuning in light-emitting devices. In addition, BE-QDS maintain their equal brightness over time
They demonstrated a first direct observation of the so-called vacuum fluctuations by using short light pulses while employing highly precise optical measurement techniques.
The duration of their light pulses was ensured to be shorter than half a cycle of light in the spectral range investigated.
when the intensity of light and radio waves completely disappears. These findings are of fundamental importance for the development of quantum physics
representing the quantum ground state of light and radio waves. However, until now direct experimental proof of this basic phenomenon has been considered impossible.
From spontaneous emission of light by excited atoms e g. in a fluorescent tube to influences on the structure of the universe during the Big Bang:
World-leading optical technologies and ultrashort pulsed laser systems of extreme stability provide the know-how necessary for this study.
#Nanoscale photodetector shows promise to improve the capacity of photonic circuits Photonic circuits, which use light to transmit signals,
It's difficult to localize visible light below its diffraction limit, about 200-300 nanometers, and as components in electronic semiconductors have shrunk to the nanometer scale,
Now researchers at the University of Rochester have demonstrated a key achievement in shrinking photonic devices below the diffraction limit--a necessary step on the road to making photonic circuits competitive with today's technology.
The scientists developed a nanoscale photodetector that uses the common material molybdenum disulfide to detect optical plasmons--travelling oscillations of electrons below the diffraction limit
--and successfully demonstrated that light can drive a current using a silver nanowire.""Our devices are a step towards miniaturization below the diffraction limit,
"said Kenneth Goodfellow, a graduate student in the laboratory of the Quantum Optoelectronics and Optical Metrology Group, The Institute of Optics, University of Rochester, New york."
"It is a step towards using light to drive, or, at least complement electronic circuitry for faster information transfer."
The device expands on previous work demonstrating that light could be transmitted along a silver nanowire as a plasmon
the light corresponded to the band gap of Mos2, rather than solely to the laser's wavelength, demonstrating that the plasmons effectively nudged the electrons in Mos2 into a different energy state."
"The natural next idea would be to see if this type of device would be able to be used as a photodetector,
"Goodfellow said. To do this, the group transferred a silver nanowire coated at one end with Mos2 onto a silicon substrate
and deposited metal contacts onto that same end with electron beam lithography. They then connected the device to equipment to control its bias,
When the uncovered end of the wire was exposed to a laser, the energy was converted into plasmons, a form of electromagnetic wave that travels through oscillations in electron density.
By scanning the wire bit-by-bit with a laser--a process known as raster scanning--the researchers were able to measure current at each point along the wire,
finding that it was sensitive to the polarization of the incoming light and was at its strongest
when the light was polarized parallel to the wire. They also found that the device was sensitive to the laser's excitation wavelength,
and performance was limited at shorter wavelengths due to ineffective plasmon propagation and at longer wavelengths due to the band gap of molybdenum disulfide."
"Full photonic circuits are some time in the future, but this work helps to feed the current effort,
Düsseldorf, Mainz, Princeton and Santa barbara, a ring of colloidal particles are localised in optical tweezers and automatically translated on a circular path,
using heat, instead of light, to measure magnetic systems at short length and time scales. Researchers led by Greg Fuchs,
The technique relies on analysis of reflected light from short laser pulses to gain information about magnetization. Unfortunately
the physics of optical diffraction limit how small a laser spot can be used, which ultimately limits the resolution of the technique.
For instance, Bartell and colleagues will be looking at using tricks from nanophotonics, such as fabricating gold antennae to excite thermal excitations confined to nanoscale dimensions o
The researchers at IBS used a multi-technique approach, combining solid-state NMR spectroscopy, simulations of molecular dynamics and X-ray crystallography.
The light-generating DNA antibody detecting nanomachine is illustrated here in action, bound to an antibody.
which generates a light signal. The sensor does need not to be activated chemically and is rapid-acting within five minutes-enabling the targeted antibodies to be detected easily, even in complex clinical samples such as blood serum."
Microscopy and scattering data gathered at the Molecular Foundry and the Advanced Light source also a DOE Office of Science user facility located at Berkeley Lab,
#Soft probing with optical tweezers Surfaces separate outside from inside, control chemical reactions, and regulate the exchange of light, heat, and moisture.
They thus play a special role in nature and technology. In the journal Nature Nanotechnology("Surface imaging beyond the diffraction limit with optically trapped spheres"),the Freiburg physicist Prof.
Dr. Alexander Rohrbach and his former Phd candidate Dr..Lars Friedrich have presented an ultra-soft surface scanning method based on an optical trap and optical forces.
An optical trap is created by a highly focused laser beam and can be used to hold or move miniscule objects.
scattered light and thermal noise. The tiny plastic sphere, the probe, appears to move in a chaotic manner inside the light trap due to the so-called thermal noise.
This displacement is detected by the laser beam scattered at the probe. In this way, the three-dimensional position of the probe is measured one million times per second."
so that the laser beam can jump a step forward for a millisecond, "explains Rohrbach.""Once there, the probe records the scattered light from the surface
and subtracts it. But before the probe can escape, the laser beam has trapped it again.""Among other things, the Freiburg researchers have used their technique to scan bacteria,
which have tiny protrusions on their surface. These so-called pili probably play a role in the communication between bacteria.
In the scheme, laser pulses, functioning as three-dimensional lenses in both time and space, can compress electron pulses to attosecond durations and sub-micrometer dimensions,
one can compress electron pulses by as much as two to three orders of magnitude in any dimension or dimensions with experimentally achievable laser pulses.
Wong's team conceived an all-optical scheme that focuses electron pulses in three dimensions by using a special type of laser mode with an intensity"valley"(or minimum) in its transverse profile,
"The pulsed laser modes successively strike the moving electrons at a slanting angle, fashioning a three-dimensional trap for the electrons."
the laser-electron interaction accelerates the back electrons and decelerates the front electrons. As the electrons propagate,
"Just as conventional lenses can be used to focus a light beam, our configuration can be used to focus an electron beam.
Among their findings is the fact that the longitudinal compression is sensitive to the laser pulse incidence angle,
Since the scheme allows laser pulses to be recycled for further compression of the same electron pulse (not restricted to the same dimension),
one is able to maximize the use of a single laser pulse and to achieve 3d compression with that single pulse.
a technique using electrons (instead of light or the eyes) to see the characteristics of a sample,
then convert that light into an electrical charge proportional to its intensity and wavelength. In the case of our eyes, the electrical impulses transmit the image to the brain.
"In this structure--unlike other photodetectors--light absorption in an ultrathin silicon layer can be much more efficient
and improve light absorption without the need for an external amplifier.""There's a built-in capability to sense weak light,
"Ma says. Ultimately, the new phototransistors open the door of possibility, he says.""This demonstration shows great potential in high-performance and flexible photodetection systems,"says Ma,
when exposed to ultraviolet light. The way tiny vessels are reconnected now includes stitches applied in microsurgery.
dissolving quickly under ultraviolet light to allow restored circulation. Smith placed the amino acid into the sequence in a way that allows precise control
when a plant uses light to break down water and carbohydrates, which are the main energy sources for the plant.
Light with photo energy can penetrate indirect band gap materials much more easily without getting absorbed
chief scientist and project leader at Honda Research Institute USA Inc."Our approach combines novel nanomaterials with continuous ultraviolet light radiation in the sensor design that have been developed in our laboratory by lead researcher Dr
the zone plates focus by diffraction--bending light as it passes the edge of a barrier.
"Essentially, it has to absorb the light completely. It's hard to find a material that doesn't reflect
Incoming light bouncing between individual silicon nanowires cannot escape the complex structure, making the material darker than dark.
graduate student Jayer Fernandes and recent graduate Aditi Kanhere--are exploring ways to integrate the lenses into existing optical detectors and directly incorporate silicon electronic components into the lenses themselves s
Each individual lens resembles a bull-eye of alternating light and dark. Arrays of lenses formed within a flexible polymer bend
the zone plates focus by diffraction--bending light as it passes the edge of a barrier.
"Essentially, it has to absorb the light completely. It's hard to find a material that doesn't reflect
Incoming light bouncing between individual silicon nanowires cannot escape the complex structure, making the material darker than dark.
graduate student Jayer Fernandes and recent graduate Aditi Kanhere--are exploring ways to integrate the lenses into existing optical detectors and directly incorporate silicon electronic components into the lenses themselves s
"I believe that this work will benefit researchers in the area of surface plasmonics by providing a new strategy/design for enhancing the surface enhanced Raman spectroscopy (SERS) detection limit,
which we might have to reexamine in light of new evidence. His team is now aiming to use cryofixation on other parts of the brain and even other types of tissue
But the fibrils that are believed to be most harmful are too tiny to be seen using an optical microscope.
so that light can now go through. This disturbance on the membrane the imprint of the protein fibers is transmitted down through the liquid crystal film,
so that it is large enough to be seen in polarized light with a simple optical microscope. Microscopic bright spots Seen through the microscope,
bright where the liquid crystal has been disturbed to let light pass. he liquid crystal is actually reporting what happening to the aggregates at the interface,
which detect strain by measuring shifts in the wavelength of light reflected by the optical fiber.
allowing light to escape. By measuring the loss of light, the researchers are able to calculate strain or other deformations.
Park said this type of flexible optical sensor could be incorporated into soft skins. Such a skin would
#A Natural light Switch: Identifying and Mapping Protein Behind Light Sensing Mechanism MIT scientists, working with colleagues in Spain, have discovered
benefit from knowing whether they are in light or darkness. The photoreceptors bind to the DNA in the dark,
such as the engineering of light-directed control of DNA transcription, or the development of controlled interactions between proteins. would be interested very in thinking about
from the International Centre for Radio astronomy Research, said scientists came to this conclusion after conducting the largest multi wavelength survey ever put together. e used as many space
and ground-based telescopes we could get our hands on to measure the energy output of over 200,000 galaxies across as broad a wavelength range as possible,
In total the team measured outputs across 21 different wavelengths from ultraviolet (characterises younger stars) to the far infrared (characterises younger stars.
but this work shows that it happening across all wavelengths p
#NASA Mars isolation experiment begins SIX people are about to shut themselves inside a dome in Hawaii for a year,
involves measuring the way light is scattered off large molecules and structures inside cells. Cancer cells can be detected
which harness the unusual properties of light-bending metamaterials, have shown theoretical promise for years. But outside of dramatic illusions made with lenses,
To redirect the short wavelengths of visible light requires tiny structures so instead early designs deflected longer wavelengths like microwaves.
Cloaks have struggled also to handle many wavelengths of light at once. Now, a team at Zhejiang University in Hangzhou, China, has taken a significant step forward by making a cloak for infrared radiation,
whose wavelengths are only just too long to see. All animals including humans emit infrared as heat.
Snakes can sense this radiation even in darkness, using it to hunt down their prey. e want to simulate the scene of catching a mouse,
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