Scatterings

Headliners, policy news and industry updates.

A New Light

New technology may offer silent, efficient lighting with warm white glow. 

A new type of lighting is at least twice as efficient as compact fluorescent bulbs and on par with LEDs, according to a team at Wake Forest University (U.S.A.) and Trinity College Dublin (Ireland). What’s more, the soft glow comes without the annoying flicker or buzz of standard fluorescent lights or the bluish tinge of LEDs. The researchers generated the light by adding carbon nanotubes to films that were part of field-induced polymer electroluminescience (FIPEL) devices  (Org. Electron., doi: 10.1016/j.orgel.2012.10.017).

Organic materials are attractive for lighting because they can be produced and processed inexpensively, but their short lifetimes are problematic. Thin-film electroluminescent materials appear to have longer lifetimes—researcher David Carroll reports having one that has lasted a decade. Because FIPELs are, essentially, a capacitor with a light emitting layer and one or two dielectric layers between the electrodes, the dielectric layers may be able to reduce the reactions between the active layer and electrodes, as well as protect the active layer from atmospheric degradation from oxygen or moisture.

Wake Forest is working with a company to manufacture the technology and plans to have it ready for consumers in the next year. —Yvonne Carts-Powell

Ultrafast Light Turns Insulator into a Conductor  

Laser may allow semiconductors to work at petahertz rates.

If you blast enough light into an insulator, it will blow up quickly or break down slowly. However, a pair of Nature papers describe using intense femtosecond laser pulses that not only do not damage the material, but that induce electrical currents into an otherwise insulating dielectric—specifically, a fused silica prism (Nature, DOI: 10.1038/nature11567; Nature, DOI: 10.1038/nature11720).

The work is exciting because insulators that can quickly change into conductors (and back into insulators again) could be used for signal switching. Today’s fastest semiconductor switching is measured in terahertz, but light-induced switching in insulators could work at petahertz rates—more than 10,000 times the rate of current electronics. In the near-term, it could also make possible petahertz metrology.

The team, led by Ferenc Krausz’s group at the Max Planck Institute of Quantum Optics (Germany), first investigated whether a small silica-glass prism could conduct current when hit with a few-cycle femtosecond pulse. Varying the time between pulses resulted in changes in the direction of the induced current. 

The second experiment tackled the turn-off speed. A thin film of silica was exposed to the same pulses. The strong optical field changes the electronic states in the glass with each oscillation cycle. These variations were tracked by a series of “snapshots” recorded by attosecond light pulses passed through the sample. The results showed that field-induced changes follow both the turn-on and turn-off behavior of the driving laser field; thus, they point to the reversibility of the field-induced effects. —Yvonne Carts-Powell

World’s Smallest Wrench Puts a New Twist on Micro-manipulation

Researchers have created the fiber-optic equivalent of the world’s smallest wrench by harnessing laser light’s ability to gently push and pull microscopic particles (Opt. Lett. 37, 5030). This virtual tool can precisely twist and turn the tiniest of particles, from living cells and DNA to microscopic motors and dynamos used in biological and physical research. The authors describe their new technique, which they dub a fiber-optic spanner (the British term for a wrench).

The innovation that distinguishes this technique from other optical tools is that it can spin or twist microscale objects in any direction and along any axis without moving any optical component. It’s able to do this because it uses flexible optical fibers rather than stationary lasers to do the work. This has the added benefit that the optical fibers can be positioned inside the human body, where they can manipulate and help study specific cells or potentially guide neurons in the spinal cord. 

X-Ray Marks the Spot

A team from the Sulpizio Cardiovascular Center at the University of California, San Diego (U.S.A.), has performed its 100th lead extraction surgery, a delicate procedure that uses X-ray and laser technology to replace the thin wiring of lifesaving heart devices such as pacemakers or implantable cardioverter-defibrillators (ICDs). The collaborative program, pioneered at U.C. San Diego, has a 100 percent success rate.

Pacemakers and ICDs deliver energy to the heart through thin, flexible wires, or “leads.”  When leads don’t work properly, the wires need to be removed and replaced.  

“Lead extraction” is a minimally invasive procedure that involves first accessing the leads through a small incision at the site of the device, just above the heart. The surgeon slides a tube or sheath with a long wire inside the vein and over the lead that needs to be removed. Using X-ray guidance, the surgeon then applies laser energy to dissolve the scar tissue around the lead. This allows the lead to be freed from the blood vessel wall and eventually from its attachment inside the heart. Once the old lead has been removed, it can be replaced with a new one.  

Getting DNA in the Picture

Researchers from the University of Genoa, Italy, recently used an electron microscope to take a remarkably detailed picture of a tightly packed bundle of DNA. While the first image of a single strand of DNA was produced using X-ray crystallography over 50 years ago, this work marked the first time that DNA was imaged with an electron microscope. 

Contrary to early press reports that stated that the image was of a single strand. It in fact, it showed entwined DNA strands that coiled in a similar way to a single strand (i.e., in a helix shape).  

Producing Steam from Sunlight

A technology that uses nanoparticles to convert solar energy directly into steam was recently reported by researchers at Rice University (U.S.A.). Unlike standard methods that involve heating the bulk of the water, this technique heats water enough to turn it to vapor just near the surface of nanoparticles (ACS Nano, doi:10.1021/nn304948h), allowing researchers to produce steam even from cold water. 

First, sunlight hits a solution containing broadly absorbing metal or carbon nanoparticles. The energy absorbed by the nanoparticles mostly creates heat at their surface, thus creating steam within a few seconds even though the temperature of the bulk fluid is low. The steam rises above the surface of the solution, but the nanoparticles stay in solution. Naomi Halas, lead scientist on the project says, “We’re not changing any of the laws of thermodynamics. We’re just boiling water in a radically different way.” 

The group’s analysis suggests that 80 percent of the energy from absorbed sunlight is converted into steam. While the steam could be used to generate electricity, the first uses are likely to be steam for sterilizing equipment or purifying water.  — Yvonne Carts-Powell

New Skin Age Index

A group of Taiwanese researchers has used a specialized microscope to peer harmlessly beneath the surface of human skin to measure natural age-related changes in the sizes of skin cells. The results can be used to study skin aging and may help provide an index for measuring the effectiveness of anti-aging skin products (Biomed. Opt. Express 4, 77).

Natural aging, the scanning showed, caused a significant increase in the overall size of cells known as basal keratinocytes—the most common cells in the outermost layer of skin—as well as in the sizes of their nuclei. Thus, the relative changes in the two types of cells can serve as an index for scoring natural, or “intrinsic,” skin aging—i.e., the aging of skin caused by programmed developmental or genetic factors.

New Hyperspectral Images of  Earth’s Auroras  

Auroras, which are created when charged particles from the sun penetrate Earth’s magnetic field, can reveal information about the Earth’s relationship with its nearest star and the way our planet responds to powerful solar storms. Hoping to expand our understanding of auroras and other fleeting atmospheric events, a team of space-weather researchers designed and built NORUSCA II, a new camera with unprecedented capabilities that can simultaneously image multiple spectral bands (Opt. Express 20, 27650). The camera was tested at the Kjell Henriksen Observatory  in Svalbard, Norway, where it produced new hyperspectral images of auroras—commonly referred to as the Northern (or Southern) Lights.

Current-generation cameras collect all the light together into one image and lack the ability to separately capture and analyze multiple slivers of the visible spectrum. That means that, if researchers want to study auroras by looking at specific bands or a small portion of the spectrum, they would have to use a series of filters to block out the unwanted wavelengths.

The new NORUSCA II hyperspectral camera achieves the same result without any moving parts, using its advanced optics to switch among all of its 41 separate optical bands in a matter of microseconds, orders of magnitude faster than an ordinary camera. 

Industry

Warren Buffet Acquires World’s Largest Solar Development 

Clean-energy developer MidAmerican Solar (Phoenix, Ariz., U.S.A.), a company controlled by Warren Buffet’s Berkshire Hathaway Inc., recently acquired Antelope Valley Solar Projects in California—the world’s largest solar development—from SunPower Corp. (San Jose, Calif., U.S.A.). SunPower will receive between $2 billion and 2.5 billion in the deal. Solar stocks surged as much as 41 percent in response to the news.

The two projects will form the world’s largest permitted solar photovoltaic power ranch, generating 579 MW of power and creating 650 construction jobs. The projects will provide renewable energy to Southern California Edison. The first AV Solar Ranch in Los Angeles County will consist of 3.7 million solar modules and provide 230 MW of power, enough to power 75,000 homes. —Valerie Coffey

New Venture Capital Firm to Focus on Quantum Tech

The Boston-based Quantum Wave Fund is the first venture capital firm focused exclusively on emerging quantum technologies. The new fund has raised $30 million in capital and expects that it could raise up to $70 million more t o support companies with novel quantum technology, such as quantum materials, quantum encryption security and quantum devices.

The fund targets early-stage companies with unique quantum-based products, investing from $2 million to $10 million to improve processes in engineering, production and marketing for preparation to enter the global market. Their team of nuclear physicists, computer scientists, and engineers with entrepreneurial experience will provide the knowledge and funds these companies need to scale up to multimillion-dollar technology businesses. —Valerie Coffey

Policy

U.S. Senate Blocks Measure to Increase Visas for STEM Grads


In December, the U.S. Senate blocked a bill intended to increase the number of immigrants with scientific expertise. The bill, called the STEM Jobs Act, was passed in November by the House of Representatives. It had been introduced by Rep. Lamar Smith, a Texas Republican.

The bill would set aside 55,000 permanent residency visas annually for foreign-born graduates of American universities who’ve earned advanced degrees in science, technology, engineering or mathematics. It would also grant temporary visas for the families of those immigrants for use while their permanent visa applications are being processed. 

Senate Democrats opposed the bill in part because the cost of the new visas are offset by eliminating the Diversity Visa Lottery Program, which provides green cards to persons from countries of traditionally lower rates of immigration. While they generally support the premise, many Democrats disagree with the “zero sum” approach and view the measure as too narrow.  Supporters counter that it would allow U.S. employers to retain talented science and technology leaders and maintain competitiveness, and that the Diversity program is outdated. While the long-term fate of STEM immigration reform is unknown, it’s clear that the STEM Act is not likely to become law in the near future. —Sarah Michaud


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