If you want to send light on a trip through optical fibres - with as little loss as possible, you should opt for infrared light, as is the case, for example, in the telecommunication networks worldwide.
For certain applications, such as spectroscopic investigations on ions or atoms, however, (laser) light in the ultraviolet range is required. But this type of light would quickly damage conventional optical fibres.
Researchers from the Max Planck Institute for the Science of Light (MPL) in Erlangen/Germany and of the QUEST Institute, based at the Physikalisch-Technische Bundesanstalt (PTB), have tested a new type of optical fibre with a hollow core and have found out that this type of optical fibre was able to guide UV laser light without being damaged and with acceptable loss.
Their investigations, which they have recently published in the journal "Optics Express", are interesting for numerous applications: besides precision spectroscopy on atoms or ions and their use in optical atomic clocks or quantum computers, fluorescence microscopy in biology, the investigation of process plasmas, combustion studies on soot or the spectroscopy of greenhouse gases would be other possible fields of application.
Optical fibres usually have a solid glass core. This glass core is coated with an optically thinner material. The laws of physics ensure that a light beam is kept inside such a fibre thanks to total reflection and that it can be transported over long distances without significant loss.
Such optical fibres are therefore widely used worldwide to transport light of different spectral ranges - from the infrared up to the visible light range. UV light, however, has a shorter wavelength and is therefore strongly absorbed by the glass used in most types of optical fibres and the fibres are quickly damaged by UV light.
At the Max Planck Institute for the Science of Light (MPL) in Erlangen, experiments with other types of optical fibre have been carried out for a few years. Now, it has turned out that a certain type of optical fibre is particularly well-suited for UV light: a microstructured photonic crystal fibre (PCF) with a so-called "Kagome structure" - a special pattern consisting of triangles and of hexagons in a regular arrangement - and a hollow core of 20 µm in diameter.
This core ensures a single-mode guiding of the light - i.e. with a spatial intensity distribution similar to the shape of a Gaussian bell-shaped curve. The crucial question was to know whether this transport was really single-mode and damage-free, and this is what the metrological experts from the QUEST Institute at PTB had to find out. Their investigations have shown that in the case of the UV beam used, with a wavelength of 280 nm, single-mode transmission was possible and that even after more than 100 hours in operation at a power of 15 mW, no UV-induced damage could be detected.
The optical fibres have even passed a first application test: the researchers at the QUEST Institute have used them successfully for their spectroscopic investigations on trapped ions. Stabilized by the new fibre, the UV laser beam allows an improved interrogation of the ions' internal state. Besides the users of such spectroscopic methods (for example in astronomy, chemistry or fundamental research in physics), this could also be useful for researchers who are developing quantum computers, since in that field, the internal states of a particle are the new digital 0s and 1s.
Dr. Michael H. Frosz, Head of Fibre Fabrication, Max Planck Institute for the Science of Light,
Günther-Scharowsky-Str. 1, 91058 Erlangen/Germany,
Phone: +49 (0)9131 6877-321,
F. Gebert, M. H. Frosz, T. Weiss, Y. Wan, A. Ermolov, N. Y. Joly, P. O. Schmidt, and P. St. J. Russell: Damage-free single-mode transmission of deep-UV light in hollow-core PCF. Optics Express 22, 15388 (2014)
Joint press release of the Max Planck Institute for the Science of Light, Erlangen/Germany, (MPL) and the QUEST Institute of the Physikalisch-Technische Bundesanstalt (PTB)
Piet O. Schmidt | Eurek Alert!
Significantly more productivity in USP lasers
06.12.2016 | Fraunhofer-Institut für Lasertechnik ILT
Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
07.12.2016 | Health and Medicine
07.12.2016 | Life Sciences
07.12.2016 | Health and Medicine