Two-photon absorption of soft X-ray free electron laser radiation by graphite near the carbon K-absorption edge

Royce K. Lam, Sumana L. Raj, Tod A. Pascal, C.D. Pemmaraju, Laura Foglia, Alberto Simoncig, Nicola Fabris, Paolo Miotti, Christopher J. Hull, Anthony M. Rizzuto, Jacob W. Smith, Riccardo Mincigrucci, Claudio Masciovecchio, Alessandro Gessini, Giovanni De Ninno, Bruno Diviacco, Eleonore Roussel, Simone Spampinati, Giuseppe Penco, Simone Di MitriMauro Trovò, Miltcho B. Danailov, Steven T. Christensen, Dimosthenis Sokaras, Tsu-Chien Weng, Marcello Coreno, Luca Poletto, Walter S. Drisdell, David Prendergast, Luca Giannessi, Emiliano Principi, Dennis Nordlund, Richard J. Saykally, Craig P. Schwartz

Research output: Contribution to journalArticle

4 Citations (Scopus)


We have examined the transmission of soft X-ray pulses from the FERMI free electron laser through carbon films of varying thickness, quantifying nonlinear effects of pulses above and below the carbon K-edge. At typical of soft X-ray free electron laser intensities, pulses exhibit linear absorption at photon energies above and below the K-edge, ∼308 and ∼260 eV, respectively; whereas two-photon absorption becomes significant slightly below the K-edge, ∼284.2 eV. The measured two-photon absorption cross section at 284.18 eV (∼6 × 10−48cm4s) is 7 orders of magnitude above what is expected from a simple theory based on hydrogen-like atoms – a result of resonance effects.
Original languageEnglish
Pages (from-to)112 - 116
Number of pages5
JournalChemical Physics Letters
Publication statusPublished - 1 Jul 2018
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Lam, R. K., Raj, S. L., Pascal, T. A., Pemmaraju, C. D., Foglia, L., Simoncig, A., Fabris, N., Miotti, P., Hull, C. J., Rizzuto, A. M., Smith, J. W., Mincigrucci, R., Masciovecchio, C., Gessini, A., De Ninno, G., Diviacco, B., Roussel, E., Spampinati, S., Penco, G., ... Schwartz, C. P. (2018). Two-photon absorption of soft X-ray free electron laser radiation by graphite near the carbon K-absorption edge. Chemical Physics Letters, 703, 112 - 116.