Measuring molecular fingerprints

Aleksandra Foltynowicz-Matyba is using new technology to develop instruments capable of detecting greenhouse gases in the atmosphere or signs of disease in exhaled air.

Aleksandra Foltynowicz-Matyba

Associate Professor in Physics

Wallenberg Academy Fellow 2015

Umeå University

Research field:
Mid-infrared optical frequency comb spectroscopy

She is fascinated by the possibility of measuring using light. When a beam of light passes through a gas, different molecules absorb light of different colors. Each molecule absorbs colors from its own spectrum.

“If we can measure how much light is absorbed, and at what wavelength, we are able to identify the type of molecular species, and its concentration in the gas,” Foltynowicz-Matyba explains.

Thousands of lasers in a single beam

Lasers emit high-intensity beams of light with a single color in a specific direction. Laser-based detection systems have many applications nowadays. They are used in industry to monitor the concentration of gases in combustion processes, and in atmospheric research to detect greenhouse gases and pollutants. The technology is also used in basic and applied research, since it offers high sensitivity and precision, along with short measuring time.

The early 2000s saw a breakthrough in the form of optical frequency combs. These are lasers that emit light in a multitude of colors, and may be described as a thousand lasers in a single beam. The colors are evenly spaced, like the teeth of a comb.

“A frequency comb emits all wavelengths simultaneously, and is capable of detecting the presence of trace amounts of molecules with great accuracy,” says Foltynowicz-Matyba.

Her research team is currently developing various detection systems using mid-infrared frequency combs. This light is beyond the visible spectrum.

“Admission as a Wallenberg Academy Fellow gives me a unique opportunity to make a bigger commitment, to take risks. Success for me will mean success for the entire team.”

“Mid-infrared light has longer wavelengths than visible light. We experience it as heat. It is absorbed by many molecular species, so it can be used to detect a long list of substances,” she explains.

Much of the project is concerned with identifying the exact wavelengths that molecules of different substances absorb. They represent the molecule’s own fingerprint.

“We need to know what the spectrum of a substance looks like in order to extract information from it. Our work will generate data that can be collected in databases, for the benefit of other researchers.”

A conventional laser with just one color in its beam usually cannot measure more than one kind of molecule at a time. To gain the full picture, the measurement must be repeated with another laser at a different wavelength.

“Results are more accurate when everything is measured at the same time,” Foltynowicz-Matyba points out.

Environmental and medical applications

Someone wanting to use optical frequency comb spectroscopy cannot simply buy a device off the shelf and push a button. The equipment has to be built from scratch.

“You need a lot of know-how, but when you’ve got it, you will be well acquainted with many fields: optics, electronics, mechanics and programming,” she says.

Her team has just built an instrument aimed for experimental combustion diagnostics. Next, they will be developing an instrument capable of measuring greenhouse gases. A third project involves detection of various molecules in exhaled air. In every breath we release around 300 substances, most of them in very small concentrations. An elevated level of certain substances may be a sign of a certain disease.

“All of these projects we will make in collaboration with experts in the different fields, since we ourselves cannot move on to, for example, clinical research.”

The equipment for the various applications currently demands quite a lot of space. Foltynowicz-Matyba believes it will be possible to develop smaller instruments that are still robust and perform well.

“I hope to take the system outside the lab during the life of the project. To measure greenhouse gases, it would be good to have a transportable unit,” she says.

Erasmus student

Foltynowicz-Matyba, who comes from Poland, applied to study at Umeå University as an exchange student on the Erasmus program. She received a scholarship to remain an extra year, completed her thesis, and became a doctoral student.

“As a student you had much greater freedom in Sweden than in Poland. It was more ‘hands on’. The climate was also more supportive. But I still benefit a lot from the solid education I received in Poland.”

She obtained a PhD in laser absorption spectroscopy, and afterwards got a postdoc position at the Joint Institute for Laboratory Astrophysics (JILA) at the University of Colorado in Boulder, U.S.A. One of the world’s leading research teams in the field of frequency combs was based there. After two years she returned to Umeå to set up her own team. Her admission as a Wallenberg Academy Fellow in 2015 represents an opportunity to allow the team and her ambitions to grow.

“With this project we will push the limits of the technique and become strong actors in the field of spectroscopy,” Foltynowicz-Matyba adds.

Text Carin Mannberg-Zackari
Translation Maxwell Arding
Photo Magnus Bergström