New extreme ultraviolet facility opens for use

September 28, 2020

Researchers have established a novel high-frequency laser facility at the University of Tokyo. The coherent extreme ultraviolet light source can reveal details of biological or physical samples with unprecedented clarity. It also allows for investigation of time-dependent phenomena such as ultrafast chemical reactions. Existing facilities for such investigations necessarily require enormous particle accelerators and are prohibitive to many researchers. This new facility should greatly improve access for a broad range of researchers.

You are probably familiar with ultraviolet (UV) light and X-rays. UV light from the sun helps your body produce vitamin D and makes solar panels generate power, and X-rays can be used to image the inside of your body to find broken bones or other ailments. But beyond these aspects, UV light and X-rays are also essential tools for the investigation of the physical world. Researchers use these forms of light to reveal details of biological, chemical and physical samples such as their makeup, structure and behavior.

Two kinds of light which are especially useful for state-of-the-art investigations into fast-acting phenomena, such as certain chemical reactions or biological processes, are coherent extreme ultraviolet (XUV) and soft X-ray pulses. These are both very precise forms of light with finely controlled parameters, akin to laser pulses, crucial for performing good rigorous experiments. However there are some drawbacks to how these beams are made.

"Facilities to produce coherent XUV and soft X-rays are huge machines based on particle accelerators -- like smaller versions of the Large Hadron Collider in Europe," said Professor Katsumi Midorikawa from the UTokyo Institute for Photon Science and Technology and RIKEN Center for Advanced Photonics. "Given the rarity of these facilities and the expense of running experiments there, it presents a barrier to many who might wish to use them. This is what prompted myself and colleagues at UTokyo and RIKEN to create a new kind of facility that we hope will be far more accessible for a greater number of researchers to use."

The new XUV source facility is much, much smaller than any that has come before it. It is housed inside a relatively modest lab underground at the University of Tokyo. The bulk of the machine is a 5-by-2-meter vacuum container housing a 100-meter-long ring, or resonator, down which a high-power laser light is stored. At two locations on this coil are pockets of special rare gases that alter characteristics of the passing laser. This results in the two separate beams of XUV and soft X-rays, which are cast onto samples undergoing investigation. Light reflected off the samples is then read by high-speed imaging sensors.

"What is really novel about our approach is that the XUV and soft X-ray pulses are extremely short but occur at very high frequencies, in the region of megahertz, or millions of cycles per second," said Midorikawa. "For perspective, established XUV facilities that use synchrotron radiation pulses also in the megahertz region have longer bursts which are less suitable for resolving dynamic phenomena. And those that use so-called X-ray-free electron laser sources have short pulses, but offer low frequencies of around 10 hertz to 100 hertz. So our facility offers the best of both worlds, with the added benefit of being only a fraction of the size and with far lower operating costs."

This new XUV source offers ultrashort pulses, useful for probing fast phenomena, and high frequencies, useful for investigating the structure and chemical properties of matter. This is possible, due to the process that creates the pulses as the laser interacts with the gas. It is called high-order harmonic generation and also because of this, the facility is the first of its kind capable of producing multiple XUV and soft X-ray beams.

"I have been working in the field of XUV generation and application for 30 years. Although high-order harmonic generation brought a breakthrough in this field, the generation efficiency and pulse repetition rate were still insufficient for many applications," said Midorikawa. "When I proposed the idea of this facility to my colleagues, they were instantly interested and we were able to acquire a suitable budget to complete it. We all hope this will open the door to new research from materials scientists, chemists and biologists who can finally access this amazing and powerful investigative tool."
Journal article

Natsuki Kanda, Tomohiro Imahoko, Koji Yoshida, Akihiro Tanabashi, A. Amani Eilanlou, Yasuo Nabekawa, Tetsumi Sumiyoshi, Makoto Kuwata-Gonokami & Katsumi Midorikawa. Opening a new route to multiport coherent XUV sources via intracavity high-order harmonic generation. Light: Science & Applications volume 9, Article number: 168 (2020).
DOI: 10.1038/s41377-020-00405-5

N.K. gratefully acknowledges the support from the special postdoctoral researcher program of RIKEN. K.M. and Y.N. thank the financial support from Grants-in-Aid for Scientific Research Nos. 26247068, 26220606, and 19H05628. This research was supported by the Photon Frontier Network Program; the Special Coordination Funds for Promoting Science and Technology; and the Center of Innovation Science program of the Ministry of Education, Culture, Sports, Science and Technology.

Useful links

Institute for Solid State Physics -
Photon Science Center -
RIKEN Center for Advanced Photonics -

Research Contacts

Professor Katsumi Midorikawa
RIKEN Center for Advanced Photonics
2-1 Hirosawa, Wako, Saitama 351-0198, JAPAN
Tel: +81-48-467-9492

Press Contact

Mr. Rohan Mehra
Division for Strategic Public Relations, The University of Tokyo
7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, JAPAN

About the University of Tokyo

The University of Tokyo is Japan's leading university and one of the world's top research universities. The vast research output of some 6,000 researchers is published in the world's top journals across the arts and sciences. Our vibrant student body of around 15,000 undergraduate and 15,000 graduate students includes over 4,000 international students. Find out more at or follow us on Twitter at @UTokyo_News_en.

University of Tokyo

Related Chemical Reactions Articles from Brightsurf:

Shedding light on how urban grime affects chemical reactions in cities
Many city surfaces are coated with a layer of soot, pollutants, metals, organic compounds and other molecules known as ''urban grime.'' Chemical reactions that occur in this complex milieu can affect air and water quality.

Seeing chemical reactions with music
Audible sound enables chemical coloring and the coexistence of different chemical reactions in a solution.

Nanocatalysts that remotely control chemical reactions inside living cells
POSTECH professor In Su Lee's research team develops a magnetic field-induced heating 'hollow nanoreactors'.

New NMR method enables monitoring of chemical reactions in metal containers
Scientists have developed a new method of observing chemical reactions in metal containers.

Levitating droplets allow scientists to perform 'touchless' chemical reactions
Levitation has long been a staple of magic tricks and movies.

Predicting unpredictable reactions
New research from the University of Pittsburgh's Swanson School of Engineering, in collaboration with the Laboratory of Catalysis and Catalytic Processes (Department of Energy) at Politecnico di Milano in Milan, Italy, advances the field of computational catalysis by paving the way for the simulation of realistic catalysts under reaction conditions.

First-time direct proof of chemical reactions in particulates
Researchers at the Paul Scherrer Institute PSI have developed a new method to analyse particulate matter more precisely than ever before.

Finding the source of chemical reactions
In a collaborative project with MIT and other universities, scientists at Argonne National Laboratory have experimentally detected the fleeting transition state that occurs at the origin of a chemical reaction.

Accelerating chemical reactions without direct contact with a catalyst
Northwestern University researchers demonstrate a chemical reaction produced through an intermediary created by a separate chemical reaction, findings that could impact environmental remediation and fuel production.

Visualizing chemical reactions, e.g. from H2 and CO2 to synthetic natural gas
Scientists at EPFL have designed a reactor that can use IR thermography to visualize dynamic surface reactions and correlate it with other rapid gas analysis methods to obtain a holistic understanding of the reaction in rapidly changing conditions.

Read More: Chemical Reactions News and Chemical Reactions Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to