Researchers funded by the Swiss National Science Foundation have made a chip-based device that can generate a laser signal with frequencies spaced in a comb-like fashion. Their work could be used in telecommunications applications and in chemical analysis.
In general, light and water waves alike stretch out and dissipate as they move further and further away from their source. However, there is a type of wave that maintains its shape as it propagates: solitons.
Researchers funded by the Swiss National Science Foundation (SNSF) have successfully produced optical solitons – light waves that retain their shape – using a microresonator. The light is composed of a range of frequencies separated very precisely by the same distance, producing what physicists call a frequency comb, since it resembles the regular spacing between the teeth of a comb.
A new record
To generate the solitons, researchers at EPFL and the Russian Quantum Center in Moscow have used microresonators. “These microscopic ring-shaped structures are made from very fine silicon nitride,” explains Tobias Kippenberg, the EPFL group leader.
“They are capable of storing for a few nanoseconds the light of the laser to which they are coupled. This period of time is sufficient for the light to circumnavigate the ring thousands of times and to accumulate there, which strongly increases the intensity of the light.” The interaction between the microresonator and the light becomes non-linear. The laser, which is normally continuous by nature, is converted into ultra-short pulses: solitons.
By adapting the parameters for manufacturing microresonators, the EPFL researchers additionally managed to generate a so-called soliton Cherenkov radiation. This broadens the frequency spectrum: the comb contains a greater number of teeth. Published in Science (*), the results have set a new record for this type of structure. The frequencies generated now extend over two thirds of an octave compared with the frequency of the laser.
“These results represent a promising advance for applications that require many widely spaced frequencies,” says Kippenberg. In the context of optical communications, one single laser would be enough to create a range of individual frequencies which could separately carry information. Chemical spectroscopy and atomic timekeeping are other potential fields of application. “We have filed a patent, since there is potential for further technological developments,” says Kippenberg.
Frequency combs, a discovery by Theodor Hänsch and John Hall that won them a Nobel Prize for Physics in 2005, are generally created using very large lasers. “The ability to produce optical frequency combs using small chips represents an interesting advance for making them more user-friendly,” says Tobias Kippenberg.
(*) V. Brasch et al.: Photonic chip–based optical frequency comb using soliton Cherenkov radiation, Science 10.1126/science.aad4811 (2015).
(Available to journalists as a PDF file from the SNSF: email@example.com)
Prof. Tobias J. Kippenberg
Laboratory of Photonics and Quantum Measurements
Tel: + 41 21 693 44 28 or +41 79 535 00 16
(Reachable from 7 January, 11.30 a.m.)
This press release can be found on the website of the SNSF:
Media - Abteilung Kommunikation | idw - Informationsdienst Wissenschaft
Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore
Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State
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,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
05.12.2016 | Power and Electrical Engineering
05.12.2016 | Materials Sciences
05.12.2016 | Power and Electrical Engineering