#$650 million commitment to Stanley Center at Broad Institute aims to galvanize mental illness research The following is adapted from a press release issued today by the Broad Institute of MIT and Harvard.
The brighter the light, the more steam is generated. The new material is able to convert 85 percent of incoming solar energy into steam a significant improvement over recent approaches to solar-powered steam generation.
and exposing it to a solar simulator a light source that simulates various intensities of solar radiation.
Lasers can also move energy between two points such as two satellites. But this requires an uninterrupted continuous path between the transmitter and the receiver
At the time he was working on various photonics projects lasers solar cells and optical fiber that all involved a phenomenon called resonant coupling.
The team used various techniques including differential scanning calorimetry dynamic light scattering and microscopy to test the separation efficiency showing more than 99.9 percent separation.
#Noninvasive brain control Optogenetics, a technology that allows scientists to control brain activity by shining light on neurons,
This technique requires a light source to be implanted in the brain, where it can reach the cells to be controlled.
using a light source outside the skull. This makes it possible to do long-term studies without an implanted light source.
The protein, known as Jaws also allows a larger volume of tissue to be influenced at once. This noninvasive approach could pave the way to using optogenetics in human patients to treat epilepsy and other neurological disorders,
Researchers then insert a light source, such as an optical fiber, into the brain to control the selected neurons.
Most of the natural opsins now used for optogenetics respond best to blue or green light.
Boyden team had identified previously two light-sensitive chloride ion pumps that respond to red light, which can penetrate deeper into living tissue.
these molecules, found in the bacteria Haloarcula marismortui and Haloarcula vallismortis, did not induce a strong enough photocurrent an electric current in response to light to be useful in controlling neuron activity.
The result of this screen, Jaws, retained its red-light sensitivity but had a much stronger photocurrent enough to shut down neural activity. his exemplifies how the genomic diversity of the natural world can yield powerful reagents that can be of use in biology and neuroscience,
the researchers were able to shut down neuronal activity in the mouse brain with a light source outside the animal head.
and was just as effective as that of existing silencers that rely on other colors of light delivered via conventional invasive illumination.
and identifying the reasons for its broadband light absorption, have been daunting tasks. This is, in part, because of the very characteristics that make it so interesting:
Typically, the constituents of a chemical compound can be determined through spectroscopy, among other tools, but in the case of eumelanin the spectrographs don show the sharp peaks that are ordinarily useful in identification.
Scanning the brain with a laser beam can produce 3-D images of neural activity, but it takes a long time to capture an image
With this kind of microscope, the light emitted by the sample being imaged is sent through an array of lenses that refracts the light in different directions.
Each point of the sample generates about 400 different points of light, which can then be recombined using a computer algorithm to recreate the 3-D structure. f you have one light-emitting molecule in your sample,
rather than just refocusing it into a single point on the camera the way regular microscopes do,
these tiny lenses will project its light onto many points. From that you can infer the three-dimensional position of where the molecule was,
which enables neuronal firing to be controlled by shining light on cells engineered to express light-sensitive proteins.
which are like tiny liquid-crystal displays (LCDS) positioned between the light source and the lens. Patterns of light and dark on the first modulator effectively turn it into a bank of slightly angled light emitters that is,
light passing through it reaches the second modulator only at particular angles. The combinations of the patterns displayed by the two modulators
With the technology that has historically been used to produce glasses-free 3-D images known as a parallax barrier simultaneously projecting eight different viewing angles would mean allotting each angle one-eighth of the light emitted by the projector
Bridge technology Passing light through two modulators can also heighten the contrast of ordinary 2-D video.
One of the problems with LCD screens is that they don enable rue black A little light always leaks through even the darkest regions of the display. ormally you have contrast of,
so that it (a) doesn block as much light and (b) gets better resolution. The second, he says,
and the solid angle of light coming out from that plane, that is fixed, Cossairt says. hat that means is that
In 2013, they reported making the first solar cell that gives off extra electrons from high-energy visible light,
which makes up almost half the sun electromagnetic radiation at the Earth surface. According to their estimates, applying their technology as an inexpensive coating on silicon solar cells could increase efficiency by as much as 25 percent.
since the distance between sensors is proportional to wavelength. In the latest issue of IEEE Transactions on Antennas and Propagation researchers in MIT s Research Laboratory for Electronics describe a new technique that could reduce the number of sensors required for terahertz
In a digital camera the lens focuses the incoming light so that light reflected by a small patch of the visual scene strikes a correspondingly small patch of the sensor array.
In lower-frequency imaging systems by contrast an incoming wave whether electromagnetic or in the case of sonar acoustic strikes all of the sensors in the array.
As long as the distance between sensors is no more than half the wavelength of the incoming wave that calculation is fairly straightforward a matter of inverting the sensors measurements.
But if the sensors are spaced farther than half a wavelength apart the inversion will yield more than one possible solution.
including environmental pollutants, ultraviolet light, and radiation. Fortunately, cells have several major DNA repair systems that can fix this damage,
which DNA damage caused by ultraviolet light goes unrepaired and leads to skin cancer. Scientists have identified also links between DNA repair and neurological, developmental,
But these photoswitches can be triggered to return to the other configuration by applying a small jolt of heat, light,
when lit up with near-infrared light. These particles can easily be manufactured and integrated into a variety of materials,
when exposed to near-infrared light. By altering the ratios of these elements, the researchers can tune the crystals to emit any color in the visible spectrum.
To manufacture the particles, the researchers used stop-flow lithography, a technique developed previously by Doyle.
Wherever pulses of ultraviolet light strike the streams a reaction is set off that forms a solid polymeric particle.
anyone could image the particles after shining near-infrared light on them with a laser pointer. The researchers are also working on a smartphone app that would further process the images
#A new angle on controlling light Light waves can be defined by three fundamental characteristics: their color (or wavelength), polarization, and direction.
While it has long been possible to selectively filter light according to its color or polarization,
But now, for the first time, MIT researchers have produced a system that allows light of any color to pass through
While the amount of light reflected at each of these interfaces is small, by combining many layers with the same properties,
most of the light can be reflected away except for that coming in at precisely the right angle and polarization.
Previous work had demonstrated ways of selectively reflecting light except for one precise angle, but those approaches were limited to a narrow range of colors of light.
and light lost to reflections, and re-emission, so the ability to selectively control those reflections could improve efficiency.
roughly 90 percent of the light coming in within that angle was allowed to pass through. While these experiments were done using layers of glass and tantalum oxide,
calls this an ngenious application. n a macroscopic scale this is equivalent to observing the world through a set of louvers that allow light to enter from one direction only,
operating as it does on the length scale of a wavelength. The team also included MIT research scientist Ivan Celanovic;
Each type is specialized to respond to a particular variety of visual input for example, light or darkness, the edges of an object,
Other known ganglion types respond only when light is turned on or off, and still others monitor the overall level of light
the researchers used a light microscope to image individual neurons in the brains of mice that had been engineered genetically so that one class of ganglions,
which add functions such as conducting electricity or emitting light. The new materials represent a simple demonstration of the power of this approach
and run the sample through a machine that detects any light emitted. Results can be plugged into the company software,
because light and oxygen damage the photosynthetic proteins. Usually plants can completely repair this kind of damage,
and other highly reactive molecules produced by light and oxygen, protecting the chloroplasts from damage.
but carbon nanotubes could act as artificial antennae that allow chloroplasts to capture wavelengths of light not in their normal range, such as ultraviolet, green,
tumors failed to spread. his elegant study sheds new light into the extracellular matrix proteins involved in various steps of the metastatic cascade,
that sheds empirical light on the inner workings of health care in the U s. The study takes advantage of Oregon recent use of a lottery to assign access to Medicaid, the government-backed health-care plan for low-income
#3-D images with only one photon per pixel Lidar rangefinders which are common tools in surveying
and in autonomous vehicle control among other applications gauge depth by emitting short bursts of laser light
In this week s issue of the journal Science researchers from MIT s Research Laboratory of Electronics (RLE) describe a new lidar-like system that can gauge depth
Since a conventional lidar system would require about 100 times as many photons to make depth estimates of similar accuracy under comparable conditions the new system could yield substantial savings in energy and time
and it works much more reliably than lidar in bright sunlight when ambient light can yield misleading readings.
All the hardware it requires can already be found in commercial lidar systems; the new system just deploys that hardware in a manner more in tune with the physics of low light-level imaging and natural scenes.
Count the photonsas Ahmed Kirmani a graduate student in MIT s Department of Electrical engineering and Computer science and lead author on the new paper explains the very idea of forming an image with only a single photon detected at each pixel location is counterintuitive.
In a conventional lidar system the laser fires pulses of light toward a sequence of discrete positions
The laser will generally fire a large number of times at each grid position until it gets consistent enough measurements between the times at
which pulses of light are emitted and reflected photons are detected that it can rule out the misleading signals produced by stray photons.
The MIT researchers system by contrast fires repeated bursts of light from each position in the grid only until it detects a single reflected photon;
So the MIT researchers system produces an initial provisional map of the scene based simply on the number of times the laser has to fire to get a photon back.
Fortunately the false readings produced by such ambient light can be characterized statistically; they follow a pattern known in signal processing as Poisson noise.
which contrasted the new system s performance with that of a conventional lidar system. They ve used a very clever set of information-theoretic techniques to extract a lot of information out of just a few photons
That could mean that you have a light source that s weak or it could be that you re interrogating a biological sample
and too much light could damage it. Our eyes are a very good example of this but other biological systems are the same.
which the location of objects is calculated by how long it takes a light signal to reflect off a surface and return to the sensor.
"Kadambi says. hat is because the light that bounces off the transparent object and the background smear into one pixel on the camera.
In a conventional Time of Flight camera, a light signal is fired at a scene where it bounces off an object
In 2011 Raskar group unveiled a trillion-frame-per-second camera capable of capturing a single pulse of light as it travelled through a scene.
Conventional cameras see an average of the light arriving at the sensor, much like the human eye, says James Davis, an associate professor of computer science at the University of California at Santa cruz. In contrast,
what happens when they take a camera fast enough to see that some light makes it from the lashback to the camera sooner,
when exposed to laser light. In the past, researchers have exploited this phenomenon to create sensors by coating the nanotubes with molecules,
the researchers shine ultraviolet light through a mask onto a stream of flowing building blocks, or oligomers.
Don Boroson on NASA s record-breaking use of laser communications Last week NASA announced that the Lunar Laser communication Demonstration (LLCD) on its Lunar Atmosphere
and Dust environment Explorer (LADEE) spacecraft had made history by using a pulsed laser beam to transmit data over the 239000 miles from the moon to Earth at a record-breaking data-download speed of 622 megabits per second (Mbps). This download speed is more than six times faster than the speed achieved by the best
LLCD also demonstrated a data-upload speed of 20 Mbps on a laser beam transmitted from a ground station in New mexico to the LADEE spacecraft in lunar orbit;
It is NASA s first space-based laser communications system. And it is by far the longest two-way laser communications link ever accomplished.
It includes signaling approaches that allow it to give errorfree performance through our turbulent atmosphere.
And the ground receiver is based on arrays of small inexpensive telescopes that are coupled fiber to highly efficient superconducting nanowires a photon counting technology that was brought to its high state of maturity by joint MIT and Lincoln Lab teams.
It has been known for years that laser communications have the potential to deliver much higher data rates and use smaller space terminals than radio-based systems.
But it has been an elusive goal to bring laser communications techniques and systems to the point where they can actually deliver on their promises.
With the success of LLCD next-generation space mission designers can now feel more comfortable in including a laser communication system as part of their design.
and those grew out of our laser communications developments from the previous 20 years. When Lincoln Lab pointed out to the NASA sponsors that the pieces could add up to this demonstration NASA made the mission happen.
#Persuading light to mix it up with matter Researchers at MIT have succeeded in producing and measuring a coupling of photons
whose electronic properties could be unedin real time simply by shining precise laser beams at them. The work pens up a new avenue for optical manipulation of quantum states of matter,
Their method involves shooting femtosecond (millionths of a billionth of a second) pulses of mid-infrared light at a sample of material and observing the results with an electron spectrometer, a specialized high-speed camera the team developed.
The researchers mixed the photons from an intense laser pulse with the exotic surface electrons on a topological insulator.
changing it from a conductor to a semiconductor just by changing the laser beam polarization. Normally, to produce such dramatic changes in a material properties,
it may be possible to do this just by shining light on it. That actually modifies how electrons move in this system.
the light does not even get absorbed. g
#Anklebot helps determine ankle stiffness For most healthy bipeds, the act of walking is given seldom a second thought:
or lights, or battery packs, or other equipment, which the mobile cubes could transport. n the vast majority of other modular systems,
which relies on near-infrared light, could help scientists learn more about diseased or infected cells as they flow through silicon microfluidic devices. his has the potential to merge research in cellular visualization with all the exciting things you can do on a silicon wafer,
a former postdoc in MIT Laser Biomedical Research center (LBRC) and one of the lead authors of a paper describing the technology in the Oct 2 issue of the journal Scientific Reports.
and colleagues took advantage of the fact that silicon is infrared transparent to and near-infrared wavelengths of light.
which works by sending a laser beam through a sample, then splitting the beam into two.
Traditional quantitative phase imaging uses a helium neon laser, which produces visible light, but for the new system the researchers used a titanium sapphire laser that can be tuned to infrared and near-infrared wavelengths.
For this study, the researchers found that light with a wavelength of 980 nanometers worked best.
Using this system, the researchers measured changes in the height of red blood cells, with nanoscale sensitivity,
through a silicon wafer similar to those used in most electronics labs. As red blood cells flow through the body,
if the wavelength of light is increased into the infrared range. The researchers are also working on modifying the system
(and paper co-author) Yoel Fink and his team, for use in photonics and other applications.
optical waveguides to carry light, hollow tubes to carry drugs, and conductive electrodes to carry electrical signals.
For example, light could be transmitted through the optical channels to enable optogenetic neural stimulation, the effects
or silence neurons with pulses of light, a method called optogenetics. Activating the projections led to compulsive sucrose-eating
while a Lidar system captures 3-D images to discern building facades from the physical environment.
That when they had to install the Lidar system, to better differentiate building facades from the surrounding environment.
They say this has the potential to lead to new kinds of light detection, thermal-management systems,
Although the two materials are structurally similar both composed of hexagonal arrays of atoms that form two-dimensional sheets they each interact with light quite differently.
The hybrid material blocks light when a particular voltage is applied to the graphene, while allowing a special kind of emission and propagation,
One of the consequences of this unusual behavior is that an extremely thin sheet of material can interact strongly with light,
while light interacting with hbn produces phonons. Fang and his colleagues found that when the materials are combined in a certain way,
The properties of the graphene allow precise control over light, while hbn provides very strong confinement and guidance of the light.
Combining the two makes it possible to create new etamaterialsthat marry the advantages of both,
says, he combination of these two materials provides a unique system that allows the manipulation of optical processes. he combined materials create a tuned system that can be adjusted to allow light only of certain specific wavelengths
comes from the ability to switch a light beam on and off at the material surface; because the material naturally works at near-infrared wavelengths, this could enable new avenues for infrared spectroscopy,
he says. t could even enable single-molecule resolution, Fang says, of biomolecules placed on the hybrid material surface.
says, his work represents significant progress on understanding tunable interactions of light in graphene-hbn.
The optical lattice was generated using two laser beams traveling in opposite directions, whose fields add up to form a sinusoidal periodic pattern in one dimension.
the group used light to ionize, or charge, neutral ytterbium atoms emerging from a small heated oven,
and then cooled them down with more laser light to just above absolute zero. The charged atoms can then be trapped using voltages applied to nearby metallic surfaces.
and ultraviolet (UV LIGHT to quickly isolate and extract a variety of contaminants from soil and water.
Brandl had synthesized previously polymers that could be cleaved apart by exposure to UV LIGHT. But he and Bertrand came to question their suitability for drug delivery,
since UV LIGHT can be damaging to tissue and cells, and doesn penetrate through the skin.
When they learned that UV LIGHT was used to disinfect water in certain treatment plants, they began to ask a different question. e thought
if they are already using UV LIGHT, maybe they could use our particles as well, Brandl says. hen we came up with the idea to use our particles to remove toxic chemicals, pollutants,
because we saw that the particles aggregate once you irradiate them with UV LIGHT. trap for ater-fearingpollutionthe researchers synthesized polymers from polyethylene glycol,
But when exposed to UV LIGHT, the stabilizing outer shell of the particles is shed, and now nrichedby the pollutants they form larger aggregates that can then be removed through filtration, sedimentation,
The magnetic insulator Shi and his team used was yttrium iron garnet grown by laser molecular beam epitaxy in his lab. The researchers placed a single-layer graphene sheet on an atomically smooth layer of yttrium iron garnet.
if light is polarized so that it runs parallel to the long axis of organic solar cell molecules it will be absorbed;
This design allowed the researchers to make the organized areas of the cell effectively invisible by controlling the polarity of light aimed at the active layer.
Conventional pigments produce colors by selectively absorbing light of different wavelengths#for example red ink appears red
A similar effect can be realized at a much smaller scale by using arrays of metallic nanostructures since light of certain wavelengths excites collective oscillations of free electrons known as plasmon resonances in such structures.
This enhanced resolution at the diffraction limit of light is critical for data storage digital imaging and security applications.
The plasmon resonance wavelength varies sensitively with the dimensions of the nanostructures. Consequently by varying the diameter of the four aluminum nanodisks in a pixel (all four nanodisks having the same diameter) the scientists were able to produce about 15 distinct colors#a good start
when struck by near-infrared light, and an outer fabric of porphyrin-phospholipids (Pop) that wraps around the core.
Paras Prasad, Phd, executive director of UB's Institute for Lasers, Photonics and Biophotonics (ILPB; and Guanying Chen, Phd, a researcher at ILPB and Harbin Institute of technology in China.
when struck by near-infrared light, and an outer fabric of porphyrin-phospholipids (Pop) that wraps around the core.
The Pop wrapper has biophotonic qualities that make it a great match for fluorescence and photoacoustic imagining.
Sequential printing of different types of QDS in a multilayer stack or in an interdigitated geometry provides strategies for continuous tuning of the effective overall emission wavelengths of the resulting QD LEDS.
and spectroscopy complemented with first principles theoretical calculations has shown that it gives rise to a system with very interesting electronic properties
#Researchers create novel nanobowl optical concentrator for organic solar cell Geometrical light trapping is a simple and promising strategy to largely improve the optical absorption and efficiency of solar cells.
Nonetheless implementation of geometrical light trapping in organic photovoltaic (OPV) is challenging due to the fact that uniform organic active layer can rarely be achieved on textured substrate.
Nanobowl optical concentrator for efficient light trapping and high-performance organic photovoltaics. Science Bulletin. DOI: 10.1007/s11434-014-0693
To do this they integrated an electromagnetic tweezers with an optical microscope and used a novel microfluidic chip to monitor the interaction of individual nanorods with two human breast cancer cell lines that express the Erbb family of receptors at different rates.
whether the crystalline structure of the materials is mismatched-lowering the manufacturing cost for a wide variety of semiconductor devices such as solar cells lasers and LEDS.
For example in photonic devices like solar cells lasers and LEDS the junction is where photons are converted into electrons or vice versa.
This manufacturing cost is a major reason why semiconductor devices such as solar cells lasers and LEDS remain very expensive.
allowing the device to project beams of colored light. Michael Mcalpine the lead researcher cautioned that the lens is designed not for actual use for one it requires an external power supply.
The researchers used tiny crystals called quantum dots to create the LEDS that generated the colored light.
Traditional manufacturing which uses lithography to create electronic components is a fast and efficient way to make multiple copies with a very high reliability.
#New technique allows low-cost creation of 3-D nanostructures Researchers from North carolina State university have developed a new lithography technique that uses nanoscale spheres to create three-dimensional (3-D) structures
Most conventional lithography uses a variety of techniques to focus light on a photosensitive film to create 2-D patterns.
or lasers-all of which are extremely expensive. Other conventional techniques use mechanical probes which are also costly.
but bend and scatter the light that passes through them in predictable ways according to the angle that the light takes when it hits the nanosphere.
The researchers control the nanolithography by altering the size of the nanosphere the duration of light exposures and the angle wavelength and polarization of light.
The researchers can also use one beam of light or multiple beams of light allowing them to create a wide variety of nanostructure designs.
We are using the nanosphere to shape the pattern of light which gives us the ability to shape the resulting nanostructure in three dimensions without using the expensive equipment required by conventional techniques Chang says.
And it allows us to create 3-D structures all at once without having to make layer after layer of 2-D patterns.
which are used commonly in lithography Zhang says. But the technique could also be used to create templates for 3-D structures using other materials.
Designing complex structures beyond the capabilities of conventional lithography More information: The paper Sculpting Asymmetric Hollow-Core Three-dimensional Nanostructures Using Colloidal Particles was published online Dec 8 in the journal Small l
Overtext Web Module V3.0 Alpha
Copyright Semantic-Knowledge, 1994-2011