Australasian Science — May-June 2017

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Researchers at Macquarie University have proven a method for
multiplying laser power using diamond, demonstrating that the
“superlaser” employed by the Death Star in Star Warsmay not
remain in the realm of science fiction. 
The research, published in Laser and Photonics Reviews , demon-
strates a concept where the power of many laser beams is trans-
ferred into a single intense output beam that can be directed at a
target. 
High-power lasers are already being investigated in areas such
as defence. “Researchers are developing high-power lasers to combat
threats to security from the increased proliferation of low-cost
drones and missile technology,” said co-author A/Prof Rich
Mildren. “High-power lasers are also needed in space applications,
including powering space vehicles and tackling the growing space
junk problem that threatens satellites.”
The key to the high-powered beam is placing an ultra-pure
diamond crystal at the point of convergence. The laser beams can
then be combined in the diamond by harnessing a cooperative
effect of the crystal that causes intense light beams to transfer their

power into a selected direction while avoiding the beam distor-

tion problems of single laser technologies.

“This discovery is technologically important as laser researchers

are struggling with increasing power beyond a certain level due to

the large challenges in handling the large heat build-up, and

combining beams from multiple lasers is one of the most promising

ways to substantially raise the power barrier,” said lead experi-

mentalist Dr Aaron McKay. 

While other methods of combining laser beams are being trialled

elsewhere in the world, beam combining in diamond has the unique

advantage of changing the colour of the laser beam. “The partic-

ular wavelength of the directed energy beam is critical to the effi-

cient transmission through the atmosphere and to reduce the eye

hazard for people, or indeed animals, who may be in the vicinity

of the beam,” Mildren said. 

Although other materials have exhibited beam-combining prop-

erties, the power-transfer effect at the heart of the device, called

Raman scattering, is particularly strong in diamond, which is also

outstanding for its ability to dissipate waste heat rapidly. 

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Diamond Design Proves Concept of a “Death Star” Laser

Gut Bacteria Help Asthma
Fibre supplements could provide a non-pharmacological treatment
for the estimated one million Australians who are failing to manage
their asthma, according to a study presented at the annual scientific
meeting of the Thoracic Society for Australia and New Zealand.
The study, conducted by The University of Newcastle’s Priority
Research Centre for Healthy Lungs, provided daily supplements of
the soluble fibre supplement inulin to a number of stable asthmatics.
Changes in asthma control, lung function and gut microbiota were
then monitored.
The study found that the fibre supplements altered the gut micro-
biome, which in turn had a positive effect on asthma control and
reduced airways inflammation. The treatment was most effective in
people who were poorly controlled at the start of the intervention.
“This groundbreaking research offers hope of a viable, comple-
mentary treatment for tens of millions of asthmatics around the
world struggling to control their asthma with existing medications,”
said lead researcher Prof Lisa Wood.
“This is the first time anyone has looked at the impact of altering
the gut microbiome on asthma control in humans. We’re at the tip
of a new paradigm for how diet can be used to treat asthma,” said
Prof Peter Gibson, President of TSANZ.
Another study presented by the group examined the impact of
fatty foods on asthma, and found that as little as a single meal high
in saturated fats worsens inflammation. This results in a temporary
narrowing of the airways, and leads to asthma symptoms such as
coughing, wheezing, shortness of breath and chest tightness.
The body of research holds particular significance for obese asth-
matics, who have some of the poorest diets and health outcomes for
asthma. “For many obese asthmatics, using puffers to control their
asthma simply isn’t working and it has doctors baffled,” Gibson said.
“With almost two out of three adult Australians obese or overweight,
this is becoming an increasingly pressing issue.”