Joaquín Fernández, Chair at the Department of Applied Physics at the Bilbao School of Engineering, is leading the team consisting of Professor Rolindes Balda and the Ramón y Cajal researcher, Ángel García Adeva. The findings have been published in Physical Review Letters, the most important magazine in its speciality. Atomic, Molecular, and Optical Physics can be viewed at in digital edition and the printed edition (volume 97, 3rd part) will be published next Friday, 21 July.
Optical cooling is a phenomenon that has sparked great interest over the last couple of decades, particularly in the field of the optical cooling of atomic gases (Bose-Einstein condensed (1)). Cooling solids using laser radiation is much more difficult and, in fact, a very small number of doped materials have been cooled, i.e. materials to which a tiny amount of ions of another element have been added. What has never been achieved to date is the cooling of materials doped with erbium.
Erbium is a metal element belonging to the Rare Earth group (2). Its ions have the property whereby when light of a certain wavelength falls on them, they are capable of amplifying them. This effect is used, for example, to construct light amplifiers in the field of optical telecommunications. To this end, in order to compensate for the weakening of the light signal as it journeys down an optic fibre, the fibre is doped with erbium ions.
In the case of the research undertaken by the UPV/EHU team, the luminous emission of erbium has been used to achieve the cooling of material in which these ions are housed by exciting these ions with laser light. This discovery is not only important for the technical difficulties involved, but also because the optical refrigeration of devices doped with erbium occur at wavelengths and potentials similar to those with which conventional diode lasers operate, thus making these materials ideal candidates for possible applications, unlike other doped materials that have previously been cooled. Amongst these applications are high-power optical fibre lasers, medical diagnostic techniques using laser (optical tomography) and phototherapy. These devices would function by means of dual laser pumping in which the light wavelengths would be used for the laser pumping and the other wavelength (close to the previous one) to produce optical cooling that would counteract the heating produced by the laser action. This heating causes a number of adverse effects. It can alter the properties and even burn the material being worked with.
The main reasons why this team of researchers have managed to obtain a net optical cooling of these erbium-doped materials are the extraordinary optical quality of the materials employed and the fact that the losses due to thermal vibrations in these are very small.
(1) Bose-Einstein condensed is an aggregated state of the material that certain materials have at very low temperatures. It is characterised by the property of a macroscopic amount of the particles of the material pass to the level of minimum energy, known as the fundamental state.
(2) Rare Earths: these are elements known as Lantanides and Actinides and have an electronic structure in which the f orbitals are incomplete. Practically all the rare earth elements have radioactive isotopes.
Garazi Andonegi | alfa
Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University
Astrophysicists explain the mysterious behavior of cosmic rays
18.08.2017 | Moscow Institute of Physics and Technology
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences