Lasers - Page 2

Carbon Sciences has been working on developing graphene-based devices for cloud computing. Now, the company announced that it has signed an agreement with the University of California, Santa Barbara (UCSB) to fund the research and development of a new graphene-based optical modulator, a critical fiber optics component needed to enable ultrafast communication in data centers for Cloud computing.

In order for data to be transmitted through a fiber optic cable, light from a laser beam must be modulated. The amount of data that can be encoded and transmitted depends on the speed of the light beam modulation. Since changing the conductivity of graphene also changes its optical properties, light passing through it will also be changed accordingly to encode digital data. This, along with graphene's impressive features are to enable the development of an ultrafast, low cost, and low power, graphene-based optical modulator.

Rice University researchers have configured their previous invention of Laser Induced Graphene (LIG) into flexible, solid-state microsupercapacitors that rival current leading ones for energy storage and delivery.

The LIG microsupercapacitors reportedly charge 50 times faster than batteries, discharge more slowly than traditional capacitors and match commercial supercapacitors for both the amount of energy stored and power delivered. The devices are made by burning electrode patterns with a commercial laser into plastic sheets in room-temperature air, eliminating the complex fabrication conditions that have limited the widespread application of microsupercapacitors.

Graphene 3D Lab has announced filing a provisional patent for a process of 3D printing an OLED light source that immediately functions when printed, with a graphene coated transparent conductor window. This unique structure is the product of an innovative multi-functional 3D Printer, which can make thin films as well as 3D structures.

The printer patent relates to a technology that should lead the industry in multiple deposition techniques, robotic manipulator, laser and UV curing capabilities. G3L considers the new IP a dramatic leap forward, offering the ability to 3D print with multiple functional materials at the same time, including the ability to 3D print a working light. This printer was reportedly designed to maximize the attributes of the functional materials that the company already developed, and plans to introduce in the future to the market.

Researchers at MIT conducted simulations and reached a new theory, according to which a sheet of graphene could be used to make X-rays. In this method, the graphene is used to generate surface waves called plasmons when the sheet is struck by photons from a laser beam. These plasmons in turn could be triggered to generate a sharp pulse of radiation, tuned to wavelengths anywhere from infrared light to X-rays.

The radiation produced by the system would be of a uniform wavelength and tightly aligned, similar to that from a laser beam. The researchers say this could potentially enable lower-dose X-ray systems in the future, making them safer. The new system could, in principle, create ultraviolet light sources on a chip and table-top X-ray devices that could produce the sorts of beams that currently require huge, multimillion-dollar particle accelerators.

Researchers at Purdue University suggest wrapping silver nanowires with an ultrathin layer of graphene can protect the structures from damage and could represent a key to realizing their commercial potential. Silver nanowires are known to hold promise for applications such as flexible displays and solar cells, but their susceptibility to damage from UV radiation and harsh environmental conditions has limited their commercialization.

The scientists state that Devices made from silver nanowires and graphene could find uses in solar cells, flexible displays for computers and consumer electronics, future "optoelectronic" circuits and more, since that graphene "extracts and spreads" most of the thermal energy away from the nanowires. Raman spectroscopy was performed by the Purdue Department of Physics and Astronomy and findings showed the graphene sheathing protected the nanowires even while being subjected to 2.5 megawatts of energy intensity per square centimeter from a high-energy laser, which vaporizes the unwrapped wires. The unwrapped wires were damaged with an energy intensity as little as .8 megawatts per square centimeter. The graphene also helps to prevent moisture damage.

An international team of scientists from Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the University of Maryland and more, have developed a graphene-based optical detector which reacts very rapidly to incident light of all different wavelengths and works at room temperature. It is reportedly the first time that a single detector has been able to monitor the spectral range from visible light to infrared radiation and right through to terahertz radiation.

The graphene detector is made of graphene on silicon carbide, along with a unique antenna. It is regarded as a comparatively simple and inexpensive construct that can cover the huge spectral range from visible light all the way to terahertz radiation, as graphene can pick up light with a very large range of photon energies and convert it into electric signals (unlike semiconductors like silicon or gallium arsenide). The broadband antenna and the right substrate were enough to supplement graphene and create the ideal conditions for this unique detector, that can be used for the exact synchronization of laser systems.

Researchers at the Georgia Institute of Technology used carbon atoms deposited on graphene with a focused electron beam process, to demonstrate a technique for creating dynamic patterns on graphene surfaces. The patterns could be used to make reconfigurable electronic circuits, which evolve over a period of hours before ultimately disappearing into a new electronic state of the graphene.

Beyond allowing fabrication of disappearing circuits, the technology could be used as a form of timed release in which the dissipation of the carbon patterns could control other processes, such as the release of biomolecules.

Scientists from Rice University have managed to embed metallic nanoparticles into their previously-developed LIG (laser-induced graphene, a flexible film with a surface of porous graphene made by exposing a common plastic to a commercial laser-scribing beam), that turn the material into a catalyst for fuel cells and various other applications.

The researchers have now found a way to enhance the product with reactive metals and turn it into "metal oxide-laser induced graphene" (MO-LIG), a new candidate to replace expensive metals like platinum in catalytic fuel-cell applications in which oxygen and hydrogen are converted to water and electricity. The scientists state that a major advantage of this process is that commercial polymers can be used, with the addition of inexpensive metal salts. They are then subjected to the laser scriber, which generates metal nanoparticles embedded in graphene. In effect, the laser generates graphene in the open air at room temperature.

Researchers from Technological Center AIMEN explored the use of ultrafast lasers as tools for graphene processing and found that laser beams can be focused to tailor the properties of graphene films in finely defined areas to produce distinct behaviors useful for various devices. The speed of the process can be higher than one m/s for drawing the micrometer-sized features. Processing speeds over 10 m/s could be attained using advanced optical scanning.

The method is based on the use of short, highly controlled laser pulses, which induce chemical changes in the carbon lattice. A single pulse of laser with a duration of several picoseconds is enough. At this timescale, the researchers demonstrated that they can pattern graphene lattices by cutting, adding external molecules or binding compounds (functional groups like oxygen or hydroxyl). As the laser spot can be focused in an area of one square micron or less, direct writing of devices on graphene can be achieved with high precision, producing nano-devices with minimal footprint and maximum efficiency.

Graphene Flagship researchers have developed a graphene-based optical fibre laser that emits pulses with durations equivalent to just a few wavelengths of the light used. This is said to be the fastest device ever created, and should be ideal for use in ultrafast spectroscopy, as well as in surgical lasers that avoid heat damage to living tissue.

Time resolution is limited by the length of the laser pulse used. The shorter the pulse, the higher the spectroscopic resolution, with the highest possible resolution defined by the cycle length of the particular light frequency employed. In the visible and near-infrared regimes, in which most ultrafast lasers operate, the ultimate pulse duration is between 2 and 5 femtoseconds. Shorter pulses require shorter wavelengths. Pulses as short as two cycles can be generated from laser cavities using a technique known as passive mode-locking.