The Optical Society) By precisely etching tiny features--smaller than a wavelength of light--onto a silicon film one thousand times thinner than a human hair, the researchers were able to select the range of colors the material would reflect,
or wavelengths of light. Those that aren't absorbed are reflected back with shorter wavelengths giving objects a blue hue and longer wavelengths appearing redder and the entire rainbow of possible combinations in between.
Changing the color of a surface, such as the leaves on the trees in autumn, requires a change in chemical make-up.
and reflect particular wavelengths of light. This type of"structural color"is much less common in nature
Controlling light with structures rather than traditional optics is not new. In astronomy, for example, evenly spaced slits known as diffraction gratings are used routinely to direct light
and spread it into its component colors. Efforts to control color with this technique, however, have proved impractical
Rather than spreading the light into a complete rainbow, however, these ridges--or bars--reflect a very specific wavelength of light.
By"tuning"the spaces between the bars, it's possible to select the specific color to be reflected.
Unlike the slits in a diffraction grating, however, the silicon bars were extremely efficient and readily reflected the frequency of light they were tuned to.
Flexibility Is the Key to Control Since the spacing, or period, of the bars is the key to controlling the color they reflect,
spaced so they can interact with a specific wavelength of light, you can change its properties
and how it interacts with light by changing its dimensions, "said Chang-Hasnain. Earlier efforts to develop a flexible,
reflecting only a portion of the light they received. Other surfaces were too thick, limiting their applications,
orange, and red-across a 39-nanometer range of wavelengths. Future designs, the researchers believe,
and reflect light with even greater efficiency. Chameleon Skin with Multiple Applications For this demonstration, the researchers created a one-centimeter square layer of color-shifting silicon.
#Silicon photonics takes the next step toward a high-bandwidth future The computing and telecommunications industries have ambitious plans for the future:
They established a method to integrate silicon photonic chips with the processor in the same package,
"IBM has been a pioneer in the area of CMOS integrated silicon photonics for more than 12 years,
"said Bert Offrein, manager of the photonics group at IBM Research-Zurich.""In addition to the silicon technology advancements at the chip-level, novel system-level integration concepts are required also to fully profit from the new capabilities silicon photonics will bring,
"he continued. Optical interconnect technology is incorporated currently into data centers by attaching discrete transceivers or active optical cables,
the United states and Japan instead proposed an integration scheme in which the silicon photonic chips are treated similarly to ordinary silicon processor chips
Challenges arise because alignment tolerances in photonics are critical (sub-micron range) and optical interfaces are sensitive to debris and imperfections,
and enables the simultaneous interfacing of many optical connections between a silicon photonic chip and the system.
The optical coupling is also wavelength and polarization insensitive and tolerant to alignment offsets of a few micrometers,
"This integration scheme has the potential to massively reduce the cost of applying silicon photonics optical interconnects in computing systems,
#Nanospheres cooled with light to explore the limits of quantum physics A team of scientists at UCL led by Peter Barker
then used lasers to cool them to within a few degrees of absolute zero. These are the key prerequisites for making an object behave according to quantum principles.
"Nanospheres were cooled with light to explore the limits of quantum physics. Image: James Millen et al. Quantum phenomena are strange and unfamiliar.
Widely-used technologies, such as laser cooling, that work for atoms won't work for such large objects,
During cavity cooling, a particle is suspended by a laser light field contained between two mirrors, which has a very carefully calibrated wavelength.
The laser light can hold the particle steady (a phenomenon known as optical tweezing) and draw motional energy out of it at the same time.
However since the laser light can sometimes actually heat the objects up this method has not been shown to work before."
"Our solution was to combine the laser beam that cools the glass particle with an electric field
which makes it levitate, "Millen explains.""The electric field also gently moves the glass particle around inside the laser beam,
helping it lose temperature more effectively.""The team are still a few degrees short of the temperature required to create quantum behaviour in the glass nanospheres,
called CLIP-for Continuous Liquid Interface Production-manipulates light and oxygen to fuse objects in liquid media,
It works by projecting beams of light through an oxygen-permeable window into a liquid resin.
Working in tandem, light and oxygen control the solidification of the resin, creating commercially viable objects that can have feature sizes below 20 microns,
"CLIP's debut coincides with the United Nation designating 2015 as the International Year of Light and Light-Based Technologies,
and inhibiting stimulated Brillouin scattering in photonic integrated circuits")."from left: Professor Benjamin Eggleton, Thomas Bttner and Moritz Merklein, researchers from CUDOS at the University of Sydney with the chalcogenide photonic chip.
This breakthrough is a fundamental advance for research in photonic chips and optical communications, said Moritz Merklein,
lead author from the Universitys School of Physics. In optical communications systems optical nonlinearities are regarded often as a nuisance,
Importantly our experiments were performed in a photonic chip. To achieve their result the scientists investigated a specific optical nonlinearity that deals with the interaction between light
and developing certain types of lasers. So we have shown that we can selectively enhance or inhibit this interaction,
which comprises a small modulation in the optical material properties, forms a bandgap for light,
which strongly effects the propagation of light, in the same way that semiconductors control the flow of electrons.
When the laser wavelength is tuned close to the edge of the bandgap the speed of light is reduced. This will greatly enhance the optical nonlinearity.
but under low light and at night, they're still vulnerable to infrared detection, "explains Alon Gorodetsky,
The current version reflects near-infrared light. Gorodetsky's team is continuing to tweak the materials,
so variants of the stickers could also work at mid-and far-infrared wavelengths. These could have applications for thwarting thermal infrared imaging.
spectral selective perfect light absorption in single layer silicon films on aluminum surface and its thermal tunability".
and chemical materials are caused by wavelength selective light absorption in organic molecules. Currently, colors on computer and iphone screens come from dye materials pre-placed on the pixels.
is because one wavelength of light is absorbed completely, explains Dr. Guo, while his student holds a collection of color samples.
A lot of colors you see in nature are due to wavelength selective light absorption in organic molecules which cannot withstand high temperatures,
Ultraviolet light destroys organic dye molecules over time, leading to color change and fading. The new technology may hold promise for many applications such as for jewelry, automotive interior trim, aviation, signage, colored keypads, electronics and wearable displays s
making them light, flexible and highly adaptable. They operate silently and are relatively cheap to produce.
however, has very little interaction with light, limiting the material's use in light emitting and absorbing applications."
"The problem with these materials is that they are just one monolayer thick, "said Koray Aydin, assistant professor of electrical engineering and computer science at Northwestern University's Mccormick School of engineering."
"So the amount of material that is available for light emission or light absorption is limited very. In order to use these materials for practical photonic and optoelectric applications,
the research is described in the March 2015 online issue of Nano Letters("Enhanced Light Emission from Large-Area Monolayer Mos2 Using Plasmonic Nanodisc Arrays").
With enhanced light emission properties, Mos2 could be a good candidate for light emitting diode technologies.
The team's next step is to use the same strategy for increasing the material's light absorption abilities to create a better material for solar cells and photodetectors."
"By shooting it with a laser beam, we were able to read out the ion that was excited in this way,
Using photoacoustic microscopy (PAM), a single wavelength, pulse-width-based technique developed in his lab, Wang,
"Using this new single wavelength, pulse-width-based method, PAM is speed capable of high imaging of the oxygen saturation of hemoglobin,
atomlike energy levels that can be probed using green laser light. Like atomic systems, the NV centers can be used as a qubit.
Like any good sensor, the NV centers are almost completely non-invasivetheir read-out with laser light does not disturb the sample they are sensing.
and PSB formed the shell to create an nversemicelle. he material is controlled easily by salt alone, rather than by a combination of several stimuli like ph, temperature or light,
and Light Extremely stiff carbon fiber components reduce the inertia and result in a high Eigenfrequency of 200hz, important for fast response, high operating frequencies,
onl prweb About PI PI is a leading manufacturer of precision motion control equipment, piezo motors, air bearing stages and hexapod parallel-kinematics for semiconductor applications, photonics, bio-nano-technology and medical engineering.
Probing a nitrogen vacancy requires zapping it with laser light, which it absorbs and re-emits.
The intensity of the emitted light carries information about the vacancy magnetic state. n the past
only a small fraction of the pump light was used to excite a small fraction of the NVS,
the Jamieson Career development Assistant professor in Electrical engineering and Computer science and one of the designers of the new device. e make use of almost all the pump light to measure almost all of the NVS.
The MIT researchers report their new device in the latest issue of Nature Physics("roadband Magnetometry and Temperature Sensing with a Light Trapping Diamond Waveguide".
engineers will need a 3-dimensional image depicting how light interacts with these objects on the nanoscale.
Unfortunately, the physics of light has thrown up a roadblock in traditional imaging techniques: the smaller the object, the lower the image's resolution in 3-D. Now, engineers at Stanford and the FOM Institute AMOLF, a research laboratory in The netherlands, have developed a technique that makes it possible to visualize the optical properties of objects that are several
The research is detailed in the current issue of Nature Nanotechnology("Nanoscale optical tomography with cathodoluminescence spectroscopy".
Both the intensity and the wavelength of the emitted photons depended on which part of the object the electron beam excited,
For instance, the gold shell at the base of the object emitted photons of shorter wavelengths than
Each pixel in this image also contained information about the wavelength of emitted photons across visible and near-infrared wavelengths.
which light interacts with this nanometer scale object.""Interpreting a 2-D image, however, can be quite limiting,
techniques to image light-matter interactions with sub-diffraction-limited resolution have been limited to 2d.""This work could enable a new era of 3d optical imaging with nanometer scale spatial and spectral resolution,
The technique can be used to probe many systems in which light is emitted upon electron excitation."
"For instance, it could be used in manufacturing LEDS to optimize the way light is emitted, or in solar panels to improve the absorption of light by the active materials."
"The technique could even be modified for imaging biological systems without the need for fluorescent labels.
Photolithography is a standard optical process for transferring micropatterns on to a substrate by exposing specific regions of the photoresist layer to ultraviolet (UV LIGHT.
Conventional photolithography relied on photomasks which protected certain regions of the substrate from the input UV LIGHT.
Areas covered by the photomasks remain intact with the base layer while the areas exposed to the UV LIGHT are washed away,
thus creating a micropattern. This technology was limited to a two-dimensional, disc-shaped design as the boundaries between the exposed and roofed regions are always in a parallel arrangement with the direction of the light.
Professor Kim research team discovered that: 1) the areas exposed to UV LIGHT lowered the concentration of oxygen
and thus resulted in oxygen diffusion; and 2) manipulation of the diffusion speed and direction allowed control of the growth,
Photoresist under UV LIGHT creates radicals which initialize a chemical reaction. These radicals are eliminated with the presence of oxygen
This suggests that the photoresist must be exposed to UV LIGHT for an extended time to completely remove oxygen for a chemical reaction to begin.
While the region affected by the UV LIGHT lowered oxygen concentration, the concentration in the untouched region remained unchanged.
This difference in the concentrations caused a diffusion of oxygen to the region under UV LIGHT.
the diffusion occurs in parallel with the direction of the UV LIGHT. When fast, the diffusion process develops horizontally,
outward from the area affected by the UV LIGHT. Professor Kim and his team proved this phenomenon both empirically and theoretically.
The paper("Probing the Molecular Architecture of Arabidopsis thaliana Secondary cell Walls Using Two-and Three-dimensional 13c Solid State Nuclear Magnetic resonance Spectroscopy")describing this work was Editors Choice for the American
NMR spectroscopy is a vital analytical tool across science. It is a powerful technique that can provide detailed information on the three-dimensional structure and dynamics of molecules in solution and the solid state e
Today the most commercially successful organic electronic devices are OLEDS (organic light emitting diodes) found in smart phone displays.
) The team was able to design an organic electronic device in which charge generated by light lived approximately 10,000 times longer than was thought previously possible.
#Graphene pushes the speed limit of light-to-electricity conversion (Nanowerk News) The efficient conversion of light into electricity plays a crucial role in many technologies,
since it allows for information carried by light to be converted into electrical information that can be processed in electrical circuits.
Graphene is an excellent material for ultrafast conversion of light to electrical signals, but so far it was known not how fast graphene responds to ultrashort flashes of light.
have demonstrated now that a graphene-based photodetector converts absorbed light into an electrical voltage at an extremely high speed.
"The new device that the researchers developed is capable of converting light into electricity in less than 50 femtoseconds (a twentieth of a millionth of a millionth of a second.
To do this, the researchers used a combination of ultrafast pulse-shaped laser excitation and highly sensitive electrical readout.
As Klaas-Jan Tielrooij comments,"the experiment uniquely combined the ultrafast pulse shaping expertise obtained from single molecule ultrafast photonics with the expertise in graphene electronics.
Thus, the energy absorbed from light is efficiently and rapidly converted into electron heat. Next, the electron heat is converted into a voltage at the interface of two graphene regions with different doping.
thus enabling the ultrafast conversion of absorbed light into electrical signals. As Prof. van Hulst states"
Koppens comments,"Graphene photodetectors keep showing fascinating performances addressing a wide range of applications
#Lanthanide-organic framework nanothermometers prepared by spray-drying A work in Advanced Functional Materials shows how spray-drying prepared MOF nanoparticles containing lanthanide metals may be used as nanothermometers operative over a wide range of temperatures
STEVE The value measured by the 3d Cell Explorer is not fluorescence intensity of an exogenous molecule like with most optical microscopes.
In contrast, Nanolives technology detects the physical refractive index of the different cell parts with resolution far beyond the diffraction limit (see Nobel prize 2014 for chemistry.
which overcomes the inherent limitations of light, and pushes it far beyond the physical limits previously thought possible.
Nanolives technology was published in Nature Photonics in 2013("Marker-free phase nanoscopy), "and has the potential to enable completely new fields of research,
The compound is based on rare earths emitting coloured light that vary in colour with the amount of oxygen present in the sample.
it will be possible to measure oxygen using the optical microscopes already present in most hospitals. Thomas Just Sørensen is Associate professor at the Department of chemistry, Nanoscience Centre, University of Copenhagen.
which emit more light as the amount of oxygen diminishes. These, however, were incapable of measuring the amount of oxygen in cells,
whether a large amount of light signal was caused by a low oxygen concentration or a large concentration of oxygen sensitive molecules.
"You simply deduct the amount of red light from the amount of green to get a precise reading of the oxygen level.
Lucky for me that optical microscopes are kitted usually out to convert colour values to numerical values",smiles the inventor.
and Sørensen utilizes near infrared light which is highly compatible with biological studies, because it penetrates deeply into tissue,
Sørensen is particularly proud that the light signals are visible in an ordinary optical light microscope. Even though he readily admits that the microscope used for the initial testing is normal only for a when considered as individual components."
"The detector and light source was the same as on light microscopes found at any hospital, but my colleague Tom Vosch has optimized the microscope to the point where everything is almost beyond the possible.
Beerotor is equipped with a mere 24 photodiodes (or pixels) distributed at the top and the bottom of its eye.
optic flow sensors could be used as an ultra-light backup system in the event of failure on a space mission4.
have been published in Nature Photonics("Deep in vivo photoacoustic imaging of mammalian tissues using a tyrosinase-based genetic reporter").
The photoacoustic imager contains a red laser, which shines pulses of light into the animal. Absorption of the light by pigmented cells produces sound waves
which travel to the surface and are detected by an ultrasound scanner. By measuring the timings of the sound waves
the device builds up a picture of the cells. Most photoacoustic scanners detect only blood vessels,
as blood cells absorb most laser light. The UCL scientists have engineered genetically tumour cells so they create tyrosinase,
This turns the cells dark brown so they absorb light from the laser and can be detected by the photoacoustic device.
just as lenses focus light and resonators (like the body of a guitar) amplify sound. They reported their findings in the May 8, 2015,
and whispering galleries are found in applications ranging from sensing, spectroscopy and communications to the generation of laser frequency combs.
Due to the light-like properties of graphene electrons, they can pass through unimpededno matter how high the barrierif they hit the barrier head on.
#Controlling swarms of robots with light and a single finger (w/video)( Nanowerk News) Using a smart tablet and a red beam of light,
A person taps the tablet to control where the beam of light appears on a floor. The swarm robots then roll toward the illumination,
When the person swipes the tablet to drag the light across the floor the robots follow.
Using a smart tablet and a red beam of light, Georgia Institute of technology researchers have created a system that allows people to control a fleet of robots with the swipe of a finger.
A person taps the tablet to control where the beam of light appears on a floor. The swarm robots then roll toward the illumination,
When the person swipes the tablet to drag the light across the floor the robots follow.
"In the Georgia Tech demonstration, each robot is constantly measuring how much light is in its local"neighborhood."
so that another can steal some of its light.""The robots are working together to make sure that each one has the same amount of light in its own area,
"said Egerstedt. The tablet-based control system has one final benefit: it was designed with everyone in mind.
and presented this device in Nature Photonics("All-plasmonic Machzehnder modulator enabling optical high-speed communication at the microscale").
The waveguide and the coupler made of silicon route the two parts of a split light beam to the gaps or from the gaps.
the light beams of the waveguides initiate electromagnetic surface waves, the so-called surface plasmons. The voltage applied to the polymer modulates the surface waves.
the surface waves initially enter the output optical waveguides as modulated light beams and are superimposed then.
The result is a light beam in whose intensity (amplitude), the digital information was encoded. In the experiment, the MZM works reliably over the entire spectral range of the broadband optical fiber networks of 1500 1600 nanometers at an electric bandwidth of 70 gigahertz with data flows of up to 108 gigabit per second.
The NAVOLCHI EU project serves to use the interaction of light and electrons in metal surfaces to develop novel components for optical data transmission between chips.
#New 2d transistor material made using precision lasers Molybdenum ditelluride (Mote2) is a crystalline compound that
They directed a 1 m wide laser (a human hair is 17 to 181 m) at the 2h-Mote2
#Using lasers to tailor the properties of graphene Carbon nanomaterials display extraordinary physical properties, outstanding among any other substance available,
The researchers from Technological Center AIMEN explore the use of ultrafast lasers as tool for graphene processing.
The laser beam can be focused precisely, used to tailor the properties of graphene films in finely defined areas,
The key is the use of short, highly controlled laser pulses, which will induce chemical changes in the carbon lattice.
It enough a single pulse of laser, with a duration of several picoseconds the time of a single oscillation in a polar molecule, like water.
As the laser spot can be focused in areas of one square micron or less, direct writing of devices on graphene can be done with high precision,
As recently published in AIP Applied Physics Letters("Patterned graphene ablation and two-photon functionalization by picosecond laser pulses in ambient conditions),
"the work of AIMEN researches demonstrated laser based large scale patterning of graphene at high speed and resolution, opening new possibilities for device making.
and chemical processes by adjusting laser beam characteristics. For low energy inputs, multiphoton absorption plays a major role, inducing chemical reactions between carbon
and atmosphere molecules, resulting in new optical properties in graphene. The potential of the altered optical properties (like spectral transmission) of functionalized graphene are just starting to be recognized,
The Laser Applications Centre of AIMEN is devoted to applied research in the field of laser materials processing,
being the largest Spanish laser center in terms of research personnel and investment. The work leading to these results was held within the European FAIERA project, funded by the European union Seventh Framework Programme (GA 316161), under the Research Potential initiative REGPOT in the Capacities Programme a
#Integration of quantum dots and photonic crystals produce brighter, more efficient light Recently, quantum dots (QDS) ano-sized semiconductor particles that produce bright, sharp,
developing a new method to extract more efficient and polarized light from quantum dots (QDS) over a large-scale area.
and photonic crystal technology, could lead to brighter and more efficient mobile phone, tablet, and computer displays, as well as enhanced LED lighting.
They then used electrohydrodynamic jet (e-jet) printing technology to precisely print the QD-embedded polymers onto photonic crystal structures.
These photonic crystals limit the direction that the QD-generated light is emitted meaning they produce polarized light,
an ECE graduate student and the lead author of the research reported this week in Applied Physics Letters("Polarized quantum dot emission in electrohydrodynamic jet printed photonic crystals),
"their replica molded photonic crystals could someday lead to brighter, less expensive, and more efficient displays. ince screens consume large amounts of energy in devices like laptops, phones,
See explained. f you put the photonic crystal-enhanced quantum dot into a device like a phone or computer,
See fabricated a novel 1mm device (aka Robot Man) made of yellow photonic crystal-enhanced QDS.
Imperial College London and the University of Buenos aires have published the results of a study testing a silicon nanodevice in the journal Nature Communications("Non-plasmonic nanoantennas for surface enhanced spectroscopies with ultra-low
"This silicon nanodevice can funnel laser light to a tightly focused spot and probe biological molecules to explore their potential use as new drugs.
such as gold and silver, are used in laser light devices because they have the ability to capture individual photons of light.
or the development of silicon computing chips that process data communicated by photons of light instead of electricity.
Common laboratory analytical techniques such as Raman and fluorescence spectroscopy determine the properties of biological molecules,
Discovery image of the planet 51 Eridani b with the Gemini Planet Imager taken in the near-infrared light on December 18 2014.
mostly as infrared light,"says Macintosh. Once the astronomers zeroed in on the star, they blocked its light
and spotted 51 Eridani b orbiting a little farther away from its parent star than Saturn does from the sun
. Even though the light from the planet is very faint nearly a million times fainter than its star subsequent observations revealed that it is roughly twice the mass of Jupiter.
and optimization of electronic and optoelectronic devices like solar panels and telecommunication lasers. black phosphorus To truly understand the significance of the team's findings,
#New optical chip lights up the race for quantum computer The microprocessor inside a computer is a single multipurpose chip that has revolutionised people's life,
Now, researchers from the University of Bristol in the UK and Nippon Telegraph and Telephone (NTT) in Japan, have pulled off the same feat for light in the quantum world by developing an optical chip that can process photons in an infinite number
and control quantum states of light and matter. A major barrier in testing new theories for quantum science and quantum computing is the time
because the world's leading quantum photonics group teamed up with Nippon Telegraph and Telephone (NTT), the world's leading telecommunications company.
Professor Jeremy O'brien, Director of the Centre for Quantum Photonics at Bristol University, explained:""Over the last decade, we have established an ecosystem for photonic quantum technologies,
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