Ultrafast Time-Resolved Hard X-Ray Emission Spectroscopy on a Tabletop

作者：Miaja Avila Luis; O' Neil Galen C; Joe Young I; Alpert Bradley K; Damrauer Niels H; Doriese William B; Fatur Steven M; Fowler Joseph W; Hilton Gene C; Jimenez Ralph; Reintsema Carl D; Schmidt Daniel R; Silverman Kevin L; Swetz Daniel S; Tatsuno Hideyuki; Ullom Joel N

来源：Physical Review X, 2016, 6(3): 031047.

DOI：10.1103/PhysRevX.6.031047

Experimental tools capable of monitoring both atomic and electronic structure on ultrafast (femtosecond to picosecond) time scales are needed for investigating photophysical processes fundamental to light harvesting, photocatalysis, energy and data storage, and optical display technologies. Time-resolved hard x-ray (> 3 keV) spectroscopies have proven valuable for these measurements due to their elemental specificity and sensitivity to geometric and electronic structures. Here, we present the first tabletop apparatus capable of performing time-resolved x-ray emission spectroscopy. The time resolution of the apparatus is better than 6 ps. By combining a compact laser-driven plasma source with a highly efficient array of microcalorimeter x-ray detectors, we are able to observe photoinduced spin changes in an archetypal polypyridyl iron complex [Fed2,2'-bipyridine)(3)](2+) and accurately measure the lifetime of the quintet spin state. Our results demonstrate that ultrafast hard x-ray emission spectroscopy is no longer confined to large facilities and now can be performed in conventional laboratories with 10 times better time resolution than at synchrotrons. Our results are enabled, in part, by a 100- to 1000-fold increase in x-ray collection efficiency compared to current techniques.

• 出版日期2016-9-27