A roadmap for ultrafast spectroscopy
How atoms and electrons respond to light determines, quite literally, how we see the world, as well as controlling vital processes like photosynthesis, solar energy generation and light emission. When light is absorbed by matter it triggers a cascade of electronic and vibrational processes as the material recovers. Light pulses provide a crucial probe of how charges, spins, and atoms move on picosecond, femtosecond, and down to attosecond timescales, none of which are accessible even with the fastest electronic devices. Ultrafast spectroscopy and imaging techniques use pulses of light to probe these fundamental interactions in materials, and strong light pulses can even drive materials into unusual phases, with exotic properties.
Researchers from the Department's Ultrafast & Terahertz Spectroscopy group and the Warwick Centre for Ultrafast Spectroscopy, along with over 20 international experts in ultrafast science, have recently released a "roadmap" for ultrafast probes of matter [1], which details the current state-of-the-art in experimental and theoretical studies, highlights challenges for the field and predicts future developments. In the 25 years since the Nobel-prize winning invention of incredibly powerful pulsed lasers [2], the technology behind creating intense pulses of light only a few femtoseconds in duration has advanced amazingly. Lab-based experiments can now probe how materials respond to UV, visible, infrared, and far-infrared (terahertz) light. The widespread adoption of these ultrafast methods has led to a vibrant research community publishing over 1000 scientific journal articles each year.
The Roadmap [1] highlights some of the exciting recent developments in ultrafast studies of condensed matter - including work on important materials such as semiconductors, superconductors and atomically-thin quantum materials. Further, the latest developments in experimental and theoretical techniques are described by international researchers at the forefront of their disciplines.
[1] J. Lloyd-Hughes et al., J. Phys.: Condens. Matter 33 353001 (2021).
[2] Nobel Prize in Physics 2018, awarded in part to Donna Strickland & Gerard Mourou for their invention of ultrafast lasers based on chirped pulse amplification.
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Ultrafast electron spectroscopy and microscopy. Image courtesy V. Pareek & K. Dani.
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Light driving magnetic moments. Image courtesy I. Radu