Diamonds Pump Up Lasers
The brightness of the output beam was 50 per cent higher than the input beam.
Lasers may bring to mind military-grade weaponry or the pew-pew sounds of science fiction blasters, but powerful laser tech can be used for less destructive purposes. Scientists and engineers are now aiming lasers at persistent problems like air turbulence, inoperable tumors and drug addiction. Here's a look at the ways zapping something with a beam of light can actually help rather than hurt.
J.P. Wolf / University of Geneva
Scientists -- and super villains -- have long wanted to control the weather with technology. What once seemed like a wild dream has become possible in theory. In late 2013, the World Meteorological Organization conference in Geneva held a Laser, Weather and Climate conference where participants discussed controlling lightning and condensation with laser assists.
More recently researchers at the University of Florida and the University of Arizona surrounded one laser beam with another, a technique they think could help a high-energy beam go greater distances.
In 2010, neurosurgeons from Washington University were among the first in the United States to use a laser probe on brain tumors thought to be inoperable. The team, led by chief of neurosurgery Ralph G. Dacey Jr., employed the new MRI-guided probe from Monteris Medical to kill cancer cells deep in a patient’s brain, leaving the surrounding tissue intact. Last year the laser probe, called the NeuroBlate Thermal Therapy System, was cleared by the Food and Drug Administration.
Laser beams could be the key to getting hearts beating correctly, an alternative to current electrode-based pacemakers that can do damage to heart muscle over the long-term. In 2010, scientists from Case Western University and Vanderbilt University successfully paced a live quail embryo heart with light from an infrared laser.
While we don’t quite have human optical pacemakers yet, a team from the University College London recently made headway with a separate laser-based technique. They’re hoping to create an “optical pacemaker” for the diaphragm that could help patients with motor neuron diseases like ALS breathe independently.
Apira Science Inc.
Apira Science Inc.’s iGrow helmet to combat baldness may not look serious at first, but the company says this low-level laser therapy has been proven effective at stimulating cell activity around weak hair follicles. The helmet interior has red laser and LED light diodes that go to work in multiple weekly sessions over several months.
Apria points to an article in the journal Lasers in Surgery and Medicine that concluded low level laser therapy improved hair counts for men with alopecia compared to a placebo light-up helmet.
B. Chen / NIDA
Could controlling addiction be as easy as flipping a switch? In 2013, scientists from the National Institutes of Health and the University of California were able to turn off compulsive behavior in rats through a combination of genetic engineering and laser light delivered through fiber optic cables. When they turned on a laser light in the brain region responsible for decision-making and impulse control, the compulsive cocaine seeking was gone, according to researcher Antonello Bonci.
While lasers were used for the study, techniques like noninvasive transcranial magnetic stimulation would probably be used for human trials.
Craik Sustainable Living Project, Flickr Creative Commons
A team from Leibniz University Hanover led by biosystems engineering professor Thomas Rath has been working on a way to eradicate pesky weeds with lasers. In 2012 he and his colleagues investigated mid-infrared range lasers as an alternative to herbicides.
A year later Leibniz University engineers shifted their focus and began studying the effects of near-infrared lasers on pests like aphids and whiteflies. They hope the right lase blast will safely kill the pests while leaving the host plants unaffected.
Last summer frequent fliers got a glimmer of hope for smoother travel. Researchers at the German Aerospace Center DLR’s Institute of Atmospheric Physics began testing technology that can detect turbulence, particularly the clear air kind that’s nearly impossible to predict. The device goes onboard a plane and emits short-wave ultraviolet laser radiation along the direction of flight, according to DLR. This reveals fluctuations in air density that indicate turbulence ahead. DRL has been testing the tech on flights in Europe with the goal of extending the detection distance to 20 miles.
lloydabell34, Flickr Creative Commons
Stanford University bioengineering, psychiatry and behavioral science professor Karl Deisseroth is a pioneer in using a technique called optogenetics, which involves genetically modifying neurons so they make a light-sensitive protein. Those cells can then be turned on or off with laser-based light.
Recently a group from University College London led by neurobiologist Linda Greensmith used optogenetics on paralyzed mice. Her group grafted genetically engineered motor neurons onto severed nerves in mice legs. Shining blue light on them restored nerve connectivity, reversing the paralysis.
Australian researchers have developed a unique method of improving the quality of high-powered laser beams using Marilyn Monroe's favorite gemstone.
A girl's best friend they might be, but diamonds also have special properties when it comes to dispersing heat. They have good optical scattering qualities too, effectively reshaping light beams.
According to the lead researcher, Dr Aaron McKay of the Photonics Research Centre at Macquarie University in Sydney, these properties make diamonds much better at producing high-quality laser beams than conventional techniques, especially for high-power lasers.
"Diamonds have a massive potential to make lasers travel much further and improve the beam quality, or more importantly the beam brightness, which allows you to focus the power of the laser beam onto a small target," he says.
To change a poor quality laser beam into a high-quality one you need to use a laser converter. But in conventional systems this always leads to a loss of power and the production of a lot of unwanted heat. Using diamond, the team found that after conversion, the quality -- or brightness -- of the output beam was 50 per cent higher than the input beam.
"Our work has demonstrated a diamond-based converter for enabling beam brightness enhancement for the first time," says McKay.
Conventional conversion techniques are electronically and optically complicated, while the heat produced causes more problems than it solves, including affecting the quality of the laser beam.
"Diamond is such an awesome material in terms of its thermal properties. It is very efficient and has up to 1000 times better heat handling capability than other materials," says McKay.
Because the technique uses a diamond measuring just millimeters in length it also means conversion can take place using a much smaller device, increasing portability.
The beam conversion occurs using a process known as Raman scattering, which not only improves the quality of the beam, but also converts its color or wavelength. The researchers used this property to convert the beam wavelength into the less dangerous 'eye-safe region'.
Lasers in this part of the spectrum are in great demand for applications including range finding, remote sensing and point-to-point communication, which is often used between navy ships.
The team plans to take the research a lot further, including adapting the concept to combine many poor-quality lasers into a single stronger beam.
"We are also looking at scaling the power up from the 15 to 20 watt level to watt levels in the hundreds. Currently the processes that don't use diamonds are limited to about 10 watts. We want to show a massive improvement in that," McKay says.