Infrared Science at Future Light Sources

In this talk, I will look at the overall directions of our accelerator-based infrared field, and how it will change as a new generation of multi-bend achromat synchrotrons and upgraded machines become world leading for x-ray science. Nearly 25 years ago, Carr, Reffner and Williams demonstrated that a synchrotron beamline coupled with an IR microscope performs at the diffraction limit in much of the mid-IR [1]. High brightness at the diffraction-limit was a hallmark of synchrotron IR beamlines for the next decades. Diffraction limited storage rings (DLSR) allows the emittance of the electron-beam to be comparable or smaller than the emittance of the x-ray photon beams produced, meaning the diffraction limit is moving well beyond the IR and into the soft- and hard-x-ray energy range. A number of new and upgraded facilities are under construction or planned to take advantage of the significant increase in brightness (brilliance) which will allow new x-ray science and a greater use of coherence-based imaging and time-based spectroscopies [2].

The synchrotron infrared community also has greater perceived competition from single wavelength and broadband laser sources, and improved detectors allowing high quality spectra and images from conventional IR sources. I will show typical characteristics of a DLSR for the infrared, look at how lasers have improved, and discuss both challenges and opportunities for the future of IR from synchrotron and FEL sources. I will use the planned ALS Upgrade [3] to a DLSR as a detailed example, but will also discuss other facilities.

[1] “Performance of an infrared microspectrometer at the NSLS,” GL Carr, JA Reffner, GP Williams, Review of Scientific Instruments, 66 (2) 1490-1492 (1995). DOI: 10.1063/1.1145951
[2] “The next ten years of X-ray science,” Makina Yabashi & Hitoshi Tanaka, Nature Photonics 11, 12–14 (2017). DOI: 10.1038/nphoton.2016.251
[3] “A New Light for Berkeley Lab—the Advanced Light Source Upgrade,” Ashley White, Kenneth Goldberg, Stephen Kevan, Daniela Leitner, David Robin, Christoph Steier & Lynn Yarris, Synchrotron Radiation News, 32:1, 32-36 (2019). DOI: 10.1080/08940886.2019.1559608

Acknowledgements: This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231.The author would like to thank his many IR colleagues over many years, many of whom are participating in WIRMS. Specific thanks in this talk go to Hans Bechtel, Paul Dumas, Larry Carr, Gwyn Williams, Christoph Steier, Alastair MacDowell, and many others.