Nav: Home

Mid-IR frequency combs enable high resolution spectroscopy for sensitive gas sensing

March 10, 2015

A frequency comb source is a light source with a spectrum containing thousands of laser lines. The development of these sources has been revolutionary for fundamental science. It has allowed the construction of a link between the optical part of the electromagnetic spectrum and the radio frequency part. As such, it has allowed researchers to determine optical frequencies with an unprecedented precision. Amongst others, frequency comb light sources have been used in optical clocks enabling precise time keeping. The enormous impact of frequency comb light sources on science was highlighted in 2005, when the Nobel Prize for physics was awarded to Prof. T. Haensch and Prof J. Hall for their work on optical frequency metrology using frequency combs.

Lately, frequency combs have been used to target more real life applications. In several experiments, it has been shown that the specific properties of the sources can be used to do fast, high-resolution spectroscopy over a broad spectrum. However, traditional comb sources are not at the right wavelength spectrum for doing spectroscopy.

Ghent University, imec, the Max Planck Institute for Quantum Optics in Garching and the Auckland University in New Zealand have developed mid-infrared frequency combs, working in the mid-infrared molecular fingerprinting region of the electromagnetic spectrum. In this wavelength region, many molecules have specific absorption bands that can be used in spectroscopy to determine the presence and concentration of these molecules in samples. The researchers successfully realized the broad frequency combs, by combining the strong light-matter interaction in silicon with its broad transparency window. By fabricating so-called nanowire silicon photonics waveguides to confine the light in a very small area waveguide, they further enhanced the strong light-matter interaction allowing them to broaden the spectrum of the frequency combs into the mid-infrared. The achievements were possible through the use of a unique pump laser source, previously developed by ICFO, Spain. The results are an important step towards a small-footprint chip scale mid-infrared frequency comb source. Such sources could act as sensitive cheap gas sensors in the mid-infrared. These would be important for example for environmental monitoring for measuring air-pollution or in medical diagnostics as a cheap tool to do breath analysis. It is worth noting that the reported work has been the result of collaboration between three grants of the European Research Council (ERC), i.e. Multicomb, Miracle and InSpectra.
[1] B. Kuyken, T. Ideguchi, S. Holzner, M. Yan, T. W. Hansch, J. Van Campenhout, P. Verheyen, S. Coen, F. Leo, R. Baets, G. Roelkens, N. Picque, An octave spanning mid-infrared frequency comb generated in a silicon nanophotonic wire waveguide, Nature Communications, 6(6310), (2015).

Caption: The strong confinement in the silicon photonic nanowire waveguide enhances the light matter interaction. The strong interactions allow to extend a frequency comb towards the mid-infrared.

Click on the picture to download the high-res version.

About the Photonics Research Group

The Photonics Research Group in the Department of Information Technology of Ghent University is active in the field of photonic integration - more specifically silicon photonics - and its applications in information and communication technology, in sensing and in life sciences.

The group puts its research focus on new concepts for photonic integrated devices and circuits and on the associated technologies and design methodologies. This includes passive and active waveguide-based photonic components, based on CMOS-compatible materials and processes as well as hybrid approaches combining silicon with other functional materials. The activities center around the telecom wavelength of 1.55 micrometer but are expanding both to longer wavelengths (mid-IR) and shorter wavelengths (visible). The infrastructure of the group includes cleanroom facilities for in-house fabrication of components as well as a variety of CAD-tools and measurement labs. The group is associated with the nano-electronics research center imec in Leuven and uses the CMOS-oriented research facilities of imec for research on silicon photonics.

About Ghent University

Ghent University (UGent) consists of 117 departments across 11 faculties and offers high-quality research-based educational programs in virtually every scientific discipline. UGent distinguishes itself as a socially committed and pluralistic university in a broad international perspective. The motto of the university is 'Dare to Think'. The university's appeal is growing every year, with about 41,000 students in 2014, of whom 11% (students) and 35% (PhD students) are international. Numerous research groups, centres and institutes have been founded over the years, becoming world-renowned in disciplines such as biotechnology, aquaculture and photonics.

Ghent University is the only Belgian university in the top 100 of both the Shanghai (70) and Times ranking (85). The University has participated in more than 200 research projects in the EU's Sixth Framework Programme (2002-2006) and in 260 projects in the Seventh Framework Programme, of which 26 ERC grants and 26 Marie Curie Fellowships. Ghent University coordinated 42 collaborative projects in FP7. The university provides excellent training opportunities to both young and experienced researchers, and is one of the fastest growing European universities in terms of research capacity and productivity.

About imec

Imec performs world-leading research in nanoelectronics. Imec leverages its scientific knowledge with the innovative power of its global partnerships in ICT, healthcare and energy. Imec delivers industry-relevant technology solutions. In a unique high-tech environment, its international top talent is committed to providing the building blocks for a better life in a sustainable society. Imec is headquartered in Leuven, Belgium, and has offices in the Netherlands, Taiwan, US, China, India and Japan. Its staff of over 2,080 people includes more than 670 industrial residents and guest researchers. In 2013, imec's revenue (P&L) totaled 332 million euro. Further information on imec can be found at

Imec is a registered trademark for the activities of IMEC International (a legal entity set up under Belgian law as a "stichting van openbaar nut"), imec Belgium (IMEC vzw supported by the Flemish Government), imec the Netherlands (Stichting IMEC Nederland, part of Holst Centre which is supported by the Dutch Government), imec Taiwan (IMEC Taiwan Co.) and imec China (IMEC Microelectronics (Shanghai) Co. Ltd.) and imec India (Imec India Private Limited).

About Max Planck Institute and the Max Planck Institute for Quantum Optics

The Max Planck Society is Germany's most successful research organization. Since its establishment in 1948, no fewer than 18 Nobel laureates have emerged from the ranks of its scientists, putting it on a par with the best and most prestigious research institutions worldwide. The more than 15,000 publications each year in internationally renowned scientific journals are proof of the outstanding research work conducted at Max Planck Institutes - and many of those articles are among the most-cited publications in the relevant field.

The currently 82 Max Planck Institutes conduct basic research in the service of the general public in the natural sciences, life sciences, social sciences, and the humanities. Max Planck Institutes focus on research fields that are particularly innovative, or that are especially demanding in terms of funding or time requirements.

Research at the Max Planck Institute of Quantum Optics concentrates on the interaction of light and matter under extreme conditions. One focus is the high-precision spectroscopy of hydrogen. In the course of these measurements Prof. Theodor W. Hänsch developed the frequency comb technique for which he was awarded the Nobel Prize for Physics in 2005. Other experiments aim at capturing single atoms and photons and letting them interact in a controlled way, thus paving the way towards future quantum computers. Theorists on the other hand are working on strategies to communicate quantum information in a most efficient way. They develop algorithms that allow the safe encryption of secret information. MPQ scientists also investigate the bizarre properties quantum-mechanical many-body systems can take on at extremely low temperatures (about one millionth Kelvin above zero). Finally light flashes with the incredibly short duration of several attoseconds (1 as is a billionth of a billionth of a second) are generated which make it possible, for example, to observe quantum-mechanical processes in atoms such as the 'tunnelling' of electrons or atomic transitions in real time.

Ghent University

Related Spectroscopy Articles:

Unraveling the optical parameters: New method to optimize plasmon enhanced spectroscopy
Plasmon enhanced spectroscopies allow to reach single molecule sensitivity and a lateral resolution even down to sub-molecular resolution.
Nanoscale spectroscopy review showcases a bright future
A new review authored by international leaders in their field, and published in Nature, focuses on the luminescent nanoparticles at the heart of many advances and the opportunities and challenges for these technologies to reach their full potential.
Researchers combine advanced spectroscopy technique with video-rate imaging
For the first time, researchers have used an advanced analytical technique known as dual-comb spectroscopy to rapidly acquire extremely detailed hyperspectral images.
Quantum logic spectroscopy unlocks potential of highly charged ions
Scientists from the PTB and the Max Planck Institute for Nuclear Physics (MPIK), both Germany, have carried out pioneering optical measurements of highly charged ions with unprecedented precision.
Spectroscopy: A fine sense for molecules
Scientists at the Laboratory for Attosecond Physics have developed a unique laser technology for the analysis of the molecular composition of biological samples.
Fluorescence spectroscopy helps to evaluate meat quality
Scientists of Sechenov University jointly with their colleagues from Australia proposed a new, quicker and cheaper way to assess meat quality.
Single-particle spectroscopy of CsPbBr3 perovskite reveals the origin low electrolumine
Researchers from Tokyo Institute of Technology (Tokyo Tech) used the method of single-particle spectroscopy to study electroluminescence in light-emitting devices.
'Resonance' raman spectroscopy with 1-nm resolution
Tip-enhanced Raman spectroscopy resolved 'resonance' Raman scattering with 1-nm resolution in ultrathin zinc oxide films epitaxially grown on a single-crystal silver surface.
Improved functional near infrared spectroscopy enables enhanced brain imaging
In an article published in the peer-reviewed SPIE publication Neurophotonics, 'High density functional diffuse optical tomography based on frequency domain measurements improves image quality and spatial resolution,' researchers demonstrate critical improvements to functional Near Infrared Spectroscopy (fNIRS)-based optical imaging in the brain.
Raman spectroscopy poised to make thyroid cancer diagnosis less invasive
Researchers have demonstrated that an optical technique known as Raman spectroscopy can be used to differentiate between benign and cancerous thyroid cells.
More Spectroscopy News and Spectroscopy Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at