Henry Kapteyn
CO-LABS presented JILA’s ultrafast imaging team, led by Fellows Margaret Murnane and Henry Kapteyn, the 2018 Governor’s Award for High-Impact Research. Murnane and Kapteyn were honored for their work in revolutionizing ultrafast and nanoscale imaging through the research and development of tabletop x-ray sources. These advancements enable real-time imaging of the structure, chemistry, and dynamics of materials at the level of small collections of atoms. The applications range from improving semiconductor devices and magnetic storage to understanding the fundamental physics and chemistry of complex materials. By designing, developing, and eventually enabling the availability of this technology through KM-Labs, Murnane and Kapteyn have enabled many curious researchers to further their discoveries.
Magnets hold cards to your fridge, and store data in your computer. They can power speakers, and produce detailed medical images. And yet, despite millennia of use, and centuries of study, magnetism is still far from fully understood.
The Kapteyn-Murnane group has come up with a novel way to use fast bursts of extreme ultraviolet light to capture how strongly electrons interact with each other in materials. This research is important for figuring out how quickly materials can change their state from insulating to conducting, or from magnetic to nonmagnetic. In the future such fast switching may lead to faster and more efficient nanoelectronics.
Dennis Gardner and his coworkers in the Kapteyn-Murnane group accomplished two major breakthroughs in imaging tiny structures much too small to be seen with visible light microscopes: (1) for the first time in the extreme ultraviolet (EUV) or soft X-ray region, they achieved a resolution smaller than the wavelength of the light; and (2) for the first time, they obtained high resolution quantitative imaging of near periodic tiny objects (structures with repetitive features).
The Kapteyn/Murnane group has measured how long it takes an electron born into an excited state inside a piece of nickel to escape from its birthplace. The electron’s escape is related to the structure of the metal. The escape is the fastest material process that has been measured before in the laboratory––on a time scale of a few hundred attoseconds, or 10-18 s. This groundbreaking experiment was reported online in Scienceon June 2, 2016. Also in Science on July 1, 2016, Uwe Bovensiepen and Manuel Ligges offered important insights into the unusual significance of this work.
Cong Chen and his colleagues in the Kapteyn/Murnane group have generated one of the most complex coherent light fields ever produced using attosecond (10-18 s) pulses of circularly polarized extreme ultraviolet (EUV) light. (The circularly polarized EUV light is shown as rotating blue sphere on the left of the picture. The complex coherent light field is illustrated with the teal, lilac, and purple structures along the driving laser beam (wide red line).
The Kapteyn/Murnane group, with Visiting Fellow Charles Durfee, has figured out how to use visible lasers to control x-ray light! The new method not only preserves the beautiful coherence of laser light, but also makes an array of perfect x-ray laser beams with controlled direction and polarization. Such pulses may soon be used for observing chemical reactions or investigating the electronic motions inside atoms. They are also well suited for studying magnetic materials and chiral molecules like proteins or DNA that come in left- and right-handed versions.
Mid-infrared (mid-IR) laser light is accomplishing some remarkable things at JILA. This relatively long-wavelength light (2–4 µm), when used to drive a process called high-harmonic generation, can produce bright beams of soft x-rays with all their punch packed into isolated ultrashort bursts. And, all this takes place in a tabletop-size apparatus. The soft x-rays bursts have pulse durations measured in tens to hundreds of attoseconds (10-18 s).