In a paper in the journal Optics Express, professor Chunlei Guo and his assistant Anatoliy Vorobyev demonstrate that by carving intricate patterns in silicon with extremely short, high-powered laser bursts, they can get liquid to climb to the top of a silicon chip like it was being sucked through a straw.

Unlike a straw, though, there is no outside pressure pushing the liquid up; it rises on its own accord. By creating nanometer-scale structures in silicon, Guo greatly increases the attraction that water molecules feel toward it. The attraction, or hydrophile, of the silicon becomes so great, in fact, that it overcomes the strong bond that water molecules feel for other water molecules.

Thus, instead of sticking to each other, the water molecules climb over one another for a chance to be next to the silicon. (This might seem like getting energy for free, but even though the water rises, thus gaining potential energy, the chemical bonds holding the water to the silicon require a lower energy than the ones holding the water molecules to other water molecules.) The water rushes up the surface at speeds of 3.5 cm per second.

Yet the laser incisions are so precise and nondestructive that the surface feels smooth and unaltered to the touch.

In a paper a few months ago in the journal Applied Physics Letters, the same researchers proved that the phenomenon was possible with metal, but extending it to silicon could have some important implications. For instance, Guo said, this work could pave the way for novel cooling systems for computers that operate much more effectively, elegantly, and efficiently than currently available options.

“Heat is definitely the number one problem deterring the design of faster conventional processors,” said Michael Scott, a professor of computer science at the University, who is not involved in this research.

Computer chips are essentially wafers of silicon covered with billions of microscopic transistors that communicate by sending electrical signals through metal wires that connect them. As technological innovations make it possible to pack astounding numbers of transistors on small pieces of silicon, computer processing speeds could increase substantially; however, the electrical current constantly surging through the chips creates a lot of heat, Scott said. If left unchecked, the heat can melt or otherwise destroy the chip components.

Most computers these days are cooled with fans. Essentially, the air around the circuit components absorbs the heat that is generated and the fan blows that hot air away from the components. The disadvantages of this method are that cold air cannot absorb very much heat before becoming hot, making fans ineffective for faster processors, and fans are noisy.

For these reasons, many companies have been eager to investigate the possibility of using liquid as a coolant instead of air. Liquids can absorb far more heat, and transmit heat much more effectively than air. So far, designers have not created liquid cooling systems that are cost-effective and energy efficient enough to become widely used in economical personal computers. Although Guo's discovery has not yet been incorporated into a prototype, he thinks that silicon that can pump its own coolant has the potential to contribute greatly to the design of future cooling systems.

via University of Rochester News.

Biolase Technology Inc. said Tuesday it received clearance to begin selling a handheld laser for use in dental cleaning procedures.

Biolase said the iLase diode laser has been cleared by the Food and Drug Administration. The laser is the size of a large pen and is operated by hand, with no foot pedals or cords. The iLase can be used in 25 different procedures, including treating gingivitis and cleaning between the gums and teeth to treat periodontal disease, the company said.

via  BusinessWeek.

A UT Dallas team’s study published in the Journal of Applied Physics expands the extraordinary capabilities of nanotechnology to include laser-powered acoustic speakers made from assemblies of carbon nanotubes.

The study confirms earlier research that carbon nanotubes that are stretched into sheets and electrically powered can produce intense sound, but researchers at UT Dallas’ Alan G. MacDiarmid NanoTech Institute have made some important advancements.

Although prior studies demonstrated that sheets of carbon nanotubes can produce sound when heated with alternating electrical current, the UT Dallas researchers have found that striking tones can be generated by vertical arrays of nanotubes, called forests, which resemble black velvet.

The team also discovered that high-quality sound can be generated when nanotube sheets or forests are struck with laser light that is modulated, or “altered,” in the acoustic frequency range.

“Nanotubes assemblies of various types are black and highly conductive,” said Dr. Mikhail Kozlov, a research scientist and the study’s lead author. “Their dark, conductive surface can be effectively heated with laser light or electricity to induce variations in the pressure of the air around the nanotubes — which we perceive as sound. It’s called the photo- or thermo-acoustic effect, and it’s the same principle Alexander Graham Bell used to produce sound on the first telephone.”

With laser excitation, no electrical contact with the nanotube speaker is required, making the speakers wireless.

“Speakers made with carbon nanotube sheets are extremely thin, light and almost transparent,” Kozlov said. “They have no moving parts and can be attached to any surface, which makes the surface acoustically active. They can be concealed in television and computer screens, apartment walls, or in the windows of buildings and cars. The almost invisible strands form films that can ‘talk.’”

In addition to filling a room with sound from invisible speakers, nanotube speakers could easily cancel sound from the noisiest neighbor or dim the roar of traffic rushing past a neighborhood, using the same principles as current sound-canceling technologies.

“The sound generation by nanotube sheets can help to achieve this effect on very large scales,” Kozlov said.

Carter Haines, a senior physics major, co-authored the journal article and assisted in putting the nanotube speakers through their paces. He is a former George A. Jeffrey NanoExplorer, who conducted research at the NanoTech Institute while in high school. He has continued to perform research in the lab as an undergraduate.

“Hands-on research like this is very important to me,” Haines said. “We had to put together the test set-up from scratch. I’ve enjoyed tinkering with small projects on my own, but the resources and the source of direction NanoTech offers allows me to explore science on a whole different level.”

Along with Kozlov and Haines, the NanoTech research team included:

* Dr. Jiyoung Oh, research associate.

* Dr. Marcio Lima, research associate.

* Dr. Shaoli Fang, associate research professor.

In addition to demonstrating that forests and sheets of nanotubes can generate sound, the team took a number of capability measurements to add to the growing list of characteristics, or properties, scientists can use in future studies. Such characterizations are especially important in new areas of research and serve as platforms of knowledge, built layer by layer, from projects like this.

Haines expressed a sentiment familiar to all researchers upon learning the journal article had been published.

“On the one hand, it’s rewarding to see something I worked on get recognized and published,” Haines said. “On the other hand, I know this is just one small thing, and if anything, it serves to remind me how much more there is to be done.”

via The Sounds of Nanoscience – UT Dallas News.

Bruce Tromberg (right), director of the Beckman Laser Institute, and UCI oncologists John Butler, David Hsiang and Rita Mehta (from left) are evaluating a breast imaging device that produces metabolic “fingerprints.”

In 2003, researchers at UC Irvine’s Beckman Laser Institute received a $7 million grant from the National Cancer Institute to standardize use of a laser imaging device they had created for better detection and diagnosis of breast cancer. The investment is beginning to pay off.

In January, the researchers reported in the journal Radiology that this laser breast scanner can accurately distinguish between malignant and benign growths, possibly offering an easy, noninvasive way to tell whether breast tumors warrant aggressive treatment. The study involved 60 subjects and will be replicated with a larger test group.

Developed by Beckman Laser Institute director Bruce Tromberg and assistant researcher Albert Cerussi, the handheld laser breast scanner employs a sophisticated new analysis method devised by UCI biomedical engineering professor Enrico Gratton and graduate student Shwayta Kukreti that produces a spectral “fingerprint” of each patient.

Unlike mammograms, the scanner provides detailed metabolic information by measuring hemoglobin, fat and water content, as well as tumor oxygen consumption and tissue density. In the study, researchers found that potentially dangerous malignant tumors and benign tumors have different metabolic fingerprints.

“The scanning method could improve detection in women with dense breast tissue who don’t do well with mammography,” says UCI surgical oncologist Dr. David Hsiang, who collaborated on the study. “It doesn’t require added contrast agents and can help make diagnosis more exact and treatment more focused.”

Younger women typically have dense breast tissue, and since breast cancer in that demographic is often more deadly, early detection is critical.

Separately, the UCI laser breast scanner is proving beneficial in evaluating the effectiveness of chemotherapy by supplying detailed data on changes in breast tumor metabolism during treatments. This information, which can be accessed quickly at bedside, lets oncologists tailor chemotherapy based on how a patient responds.

“The use of chemotherapy for tumor reduction prior to surgery is important with certain types of breast cancer,” says UCI surgical oncologist Dr. John Butler. “The metabolic fingerprint the scanner provides indicates how the chemotherapy is working and allows doctors to adjust treatments as needed.”

Currently, Beckman Laser Institute researchers are collaborating with colleagues at the University of Pennsylvania, Dartmouth College, UC San Francisco and Massachusetts General Hospital on a planned five-center clinical study of the device’s utility in chemotherapy. (In addition, the Bay Area biotechnology company FirstScan has licensed it for commercial applications.)

“This is a valuable opportunity to standardize our approach and determine – in a national multicenter trial – how this new technology can best enhance treatment and quality of life for breast cancer patients,” Tromberg says.

via UC Irvine Feature: Breast Tumor.

Sarah O’Hana is a silversmith with a difference, she fuses art with science to make jewellery using an industrial laser.

As part of her doctorate at Manchester University, she discovered how to use a laser to mark vibrant colours onto titanium, to produce a range of unique and contemporary jewellery.

via Telegraph.

NYC, British pop singer Little Boots used a huge laser harp on stage.

via Gizmodo.

Terminator was released in 1984, and while laser sights on weapons are common now, when the film was first shown the red laser was able to communicate something subtle and powerful to the audience: this is a machine, deadly accurate and futuristic. It made the Terminator seem other-worldly and terrifying.

Arstechnica found the true story behind the terminator’s laser-sighted gun. It is a gentleman named Ed Reynolds who created that laser. At the time, he has to use He Ne laser, which needs a high voltage power supply.

via

Jenoptik has opened the doors to a new laser application centre based in the the southern Korean city of Pyeongtaek. The company has invested $4.4 million (€3.4 million) in the centre, which houses laser processing systems ideal for customers looking to do everything from initial testing through to pilot and small production runs. New laser application centre targets the electronics, photovoltaics and flat-panel display markets

via optics.org.

The newly developed RGB laser module uses semiconductor diodes for the red and blue lasers, and a compact, high power solid-state SHG laser for the green. Both the red and green lasers were developed internally by Sony. The three lasers generate output power of 10W for red, 6W for green, and 5W for blue, resulting in a total of 21W. Furthermore, energy conversion ratios for the lasers range from 15 to 22% (18% on average), representing extremely high efficiency for power visible lasers. This high energy conversion ratio also realizes low energy consumption within the module itself.

via asahi.com.

The report on this work, entitled “Reinventing avalanche photodetectors for on-chip optical interconnects” by Solomon Assefa, Fengnian Xia and Yurii A. Vlasov of IBM’s T.J. Watson Research Center in Yorktown Heights, N.Y. is published in March 4 issue of the journal Nature.

via IBM Research .