Lasers with a wavelength of two microns could move the boundaries of surgery and molecule detection. Researchers at EPFL have managed to generate such lasers using a simple and inexpensive method
In recent years, two-micron lasers (0.002 millimetre) have been of growing interest among researchers. In the areas of surgery and molecule detection, for example, they offer significant advantages compared to traditional, shorter-wavelength lasers.
However, two-micron lasers are still in their infancy and not yet as mature as their telecom counterparts (1.55-micron). Moreover sources currently used in labs are typically bulky and expensive. Optical fibre-based 2 micron lasers are an elegant solution to these issues. This is where researchers at Photonics Systems Laboratory (PHOSL) come in.
In an article published in Light: Science & Applications, the team of Camille Brès at EPFL described a way to design these lasers at a lower cost, by changing the way optical fibres are connected to each other.
Thanks to the new configuration, they were able not only to produce very good 2 micron lasers, but also to do without an expensive and complex component that is normally required.
Bloodless surgery and long-range molecule détection
Two-micron spectral domain has potential applications in medicine, environmental sciences and industry. At these wavelengths, the laser light is easily absorbed by water molecules, which are the main constituents of human tissue.
In the realm of high precision surgery, they can be used to target water molecules during an operation and make incisions in very small areas of tissue without penetrating deeply. What is more, the energy from the laser causes the blood to coagulate on the wound, which prevents bleeding.
Two-micron lasers are also very useful for detecting key meteorological data over long distances through the air. Not to mention that they are highly effective in the processing of various industrial materials.
Replacing a cop with a detour
To create a 2 micron fibre-laser, light is usually injected into an optical-fibre ring containing a gain region which amplifies 2 micron light. The light circulates in the ring, passing through the gain region many times thus gaining more and more power, until becoming a laser. For optimal operation, these systems include a costly component called isolator, which forces the light to circulate in a single direction.
At PHOSL, researchers built a thulium-doped fibre laser that works without an isolator. Their idea was to connect the fibres differently, to steer light instead of stopping it.
"We plug a kind of deviation that redirects the light heading in the wrong direction, putting it back on track", said Camille Brès. This means no more need for the isolator, whose job is to stop light moving in the wrong direction, sort of like a traffic cop. "We replaced the traffic cop with a detour," said Svyatoslav Kharitonov, the article's lead author.
Higher quality laser
The new system not only proved to be less expensive than more traditional ones, it also showed it could generate a higher quality laser light. The explanation is as follows: the laser output gets purified because light interacts with itself in a very special way, thanks to the amplifying fibre's composition and dimensions, and the high power circulating in this atypical laser architecture.
"While the association of amplifying fibres and high power usually weakens traditional lasers performance, it actually improves the quality of this laser, thanks to our specific architecture", said Svyatoslav Kharitonov.
Publication: Light: Science & Applications, Isolator-free unidirectional thulium doped fibre laser
Camille Bres | EurekAlert!
Adhesive Process Developed for Shingle Cell Technology
09.01.2019 | Fraunhofer-Institut für Solare Energiesysteme ISE
Seawater turns into freshwater through solar energy: A new low-cost technology
08.01.2019 | Politecnico di Torino
World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles
The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.
Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.
In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...
Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.
It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:
The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.
One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...
Just in time for Christmas, a Mars-analogue mission in Morocco, coordinated by the Robotics Innovation Center of the German Research Center for Artificial Intelligence (DFKI) as part of the SRC project FACILITATORS, has been successfully completed. SRC, the Strategic Research Cluster on Space Robotics Technologies, is a program of the European Union to support research and development in space technologies. From mid-November to mid-December 2018, a team of more than 30 scientists from 11 countries tested technologies for future exploration of Mars and Moon in the desert of the Maghreb state.
Close to the border with Algeria, the Erfoud region in Morocco – known to tourists for its impressive sand dunes – offered ideal conditions for the four-week...
16.01.2019 | Event News
14.01.2019 | Event News
12.12.2018 | Event News
17.01.2019 | Physics and Astronomy
17.01.2019 | Materials Sciences
17.01.2019 | Information Technology