Saturable Absorption of Free-Electron Laser Radiation by Graphite near the Carbon K-Edge

Journal Article · Tue Sep 27 00:00:00 EDT 2022 · Journal of Physical Chemistry Letters

DOI:https://doi.org/10.1021/acs.jpclett.2c01020· OSTI ID:1889756

Hoffmann, Lars ^[1]; Jamnuch, Sasawat ^[2]; Schwartz, Craig P. ^[3]; Helk, Tobias ^[4]; Raj, Sumana L. ^[5]; Mizuno, Hikaru  ^[6]; Mincigrucci, Riccardo ^[7]; Foglia, Laura ^[7]; Principi, Emiliano ^[7]; Saykally, Richard J.  ^[6]; Drisdell, Walter S.  ^[8]; Fatehi, Shervin  ^[9]; Pascal, Tod A.  ^[10]; Zuerch, Michael  ^[11]

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1. Department of Chemistry, University of California, Berkeley, California 94720, United States, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States, Fritz Haber Institute of the Max Planck Society, 14195 Berlin, Germany
2. ATLAS Materials Science Laboratory, Department of Nano Engineering and Chemical Engineering, University of California San Diego, La Jolla, California 92023, United States
3. Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States, Nevada Extreme Conditions Laboratory, University of Nevada, Las Vegas, Las Vegas, Nevada 89154, United States
4. Institute of Optics and Quantum Electronics, Abbe Center of Photonics, Friedrich-Schiller University, 07743 Jena, Germany, Helmholtz Institute Jena, 07743 Jena, Germany
5. Department of Chemistry, University of California, Berkeley, California 94720, United States
6. Department of Chemistry, University of California, Berkeley, California 94720, United States, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
7. Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, 34149 Trieste, Italy
8. Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States, Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
9. Department of Chemistry, The University of Texas Rio Grande Valley, Edinburg, Texas 78539, United States
10. ATLAS Materials Science Laboratory, Department of Nano Engineering and Chemical Engineering, University of California San Diego, La Jolla, California 92023, United States, Materials Science and Engineering, University of California San Diego, La Jolla, California 92023, United States, Sustainable Power and Energy Center, University of California San Diego, La Jolla, California 92023, United States
11. Department of Chemistry, University of California, Berkeley, California 94720, United States, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States, Fritz Haber Institute of the Max Planck Society, 14195 Berlin, Germany, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States

The interaction of intense light with matter gives rise to competing nonlinear responses that can dynamically change material properties. Prominent examples are saturable absorption (SA) and two-photon absorption (TPA), which dynamically increase and decrease the transmission of a sample depending on pulse intensity, respectively. The availability of intense soft X-ray pulses from free-electron lasers (FELs) has led to observations of SA and TPA in separate experiments, leaving open questions about the possible interplay between and relative strength of the two phenomena. Here, we systematically study both phenomena in one experiment by exposing graphite films to soft X-ray FEL pulses of varying intensity. By applying real-time electronic structure calculations, we find that for lower intensities the nonlinear contribution to the absorption is dominated by SA attributed to ground-state depletion; our model suggests that TPA becomes more dominant for larger intensities (>10¹⁴ W/cm²). Our results demonstrate an approach of general utility for interpreting FEL spectroscopies.

• Research Organization: University of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); US Army Research Laboratory (USARL); US Army Research Office (ARO)
• Grant/Contract Number: AC02-05CH11231; SC0004993; 107573; W911NF-13-1-0483; W911NF-17-1-0163
• OSTI ID: 1889756
• Alternate ID(s): OSTI ID: 1891320; OSTI ID: 1959800
• Journal Information: Journal of Physical Chemistry Letters, Journal Name: Journal of Physical Chemistry Letters Vol. 13 Journal Issue: 39; ISSN 1948-7185
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Absorption
Anode materials
Carbon
Energy
X-rays