Precise molecular fingerprinting on the fly
Time-domain interference signal of the beats between the two frequency-agile laser combs and part of the resulting spectrum of the CO2 molecule. Graphic: MPQ, Laser Spectroscopy Division
Electro-optic modulators, which can switch light on and off within just picoseconds, are enabling ever faster telecommunication over optical glass fibres, so that large movies can be streamed more smoothly across oceans into our homes.
The same tools have now been harnessed for high-speed and accurate molecular sensing, as reported by an international collaboration around Dr. Nathalie Picqué, Max Planck Institute of Quantum Optics and Ludwig-Maximilians-Universität Munich, in a letter published in Nature Photonics, 21 December 2015. The collaboration partners are with the Laboratoire Interdisciplinaire Carnot de Bourgogne (France) and the Institut des Sciences Moléculaires d’Orsay (France).
Molecules absorb light at well-defined particular colours or optical frequencies. Usually such characteristic frequencies are located in the infrared region of the electromagnetic spectrum. Precisely measuring a set of such absorption dips unambiguously identifies the molecules and quantifies their abundance in the probed environment.
Because detection of molecules by optical absorption spectroscopy is sensitive and nonintrusive, it finds an increasing number of applications, from biomedical diagnostics to atmospheric sensing. In the gas phase, the absorption lines are narrow so that high spectral resolution is needed to distinguish the different lines. Although many powerful spectroscopic techniques have been developed, rapid and precise high-resolution sensing is still a challenge.
A team of scientists at MPQ reports a promising new technique of near-infrared spectroscopy. They use modulators and a nonlinear optical fibre to produce two frequency combs, each with more than a thousand evenly spaced infrared spectral lines with a remarkably flat intensity distribution.
Line spacing and spectral position can be selected quickly and freely by simply dialing a knob. Such frequency-agile optical combs offer unprecedented freedom when interrogating a molecular spectrum via a powerful technique called multiplexed dual-comb spectroscopy.
Two mutually coherent combs are combined in an interferometer. Unprecedented refresh rates (80 kHz) and tuning speeds (10 nm s to the minus 1) at high signal-to-noise ratio are achieved. Such unique combination holds much promise for trace gas sensing, a domain relevant to physics, biology, chemistry, industry or atmospheric sciences.
“Furthermore, the frequency-agile frequency comb generator might also become an enabling tool for applications beyond spectroscopy, like for arbitrary waveform generation, radio-frequency photonics, optical coherence tomography or microscopy”, concludes Dr. Ming Yan, a post-doc working at the experiment.
Original publication:
G. Millot, S. Pitois, M. Yan, T. Hovhannisyan, A. Bendahmane, T.W. Hänsch, N. Picqué
Frequency-agile dual-comb spectroscopy
Nature Photonics, Advance online publication, http://dx.doi.org/10.1038/nphoton.2015.250 (December 21st, 2015)
contact:
Dr. Nathalie Picqué
Max-Planck-Institut für Quantenoptik
Hans-Kopfermann-Str. 1
85748 Garching b. München
Telefon: +49 (0)89 / 32 905 -290
E-Mail: nathalie.picque@mpq.mpg.de
Dr. Olivia Meyer-Streng
Presse- und Öffentlichkeitsarbeit
Max-Planck-Institut für Quantenoptik, Garching b. München
Telefon: +49 (0)89 / 32 905 -213
E-Mail: olivia.meyer-streng@mpq.mpg.de
Media Contact
More Information:
http://www.mpq.mpg.de/All latest news from the category: Physics and Astronomy
This area deals with the fundamental laws and building blocks of nature and how they interact, the properties and the behavior of matter, and research into space and time and their structures.
innovations-report provides in-depth reports and articles on subjects such as astrophysics, laser technologies, nuclear, quantum, particle and solid-state physics, nanotechnologies, planetary research and findings (Mars, Venus) and developments related to the Hubble Telescope.
Newest articles
First-of-its-kind study uses remote sensing to monitor plastic debris in rivers and lakes
Remote sensing creates a cost-effective solution to monitoring plastic pollution. A first-of-its-kind study from researchers at the University of Minnesota Twin Cities shows how remote sensing can help monitor and…
Laser-based artificial neuron mimics nerve cell functions at lightning speed
With a processing speed a billion times faster than nature, chip-based laser neuron could help advance AI tasks such as pattern recognition and sequence prediction. Researchers have developed a laser-based…
Optimising the processing of plastic waste
Just one look in the yellow bin reveals a colourful jumble of different types of plastic. However, the purer and more uniform plastic waste is, the easier it is to…