Seeded free electron lasers theoretically have the intensity, tunability, and resolution required for multiphoton spectroscopy of atomic and molecular species. Using the seeded free electron laser FERMI and a novel detection scheme, we have revealed the two-photon excitation spectra of dipole-forbidden doubly excited states in helium. The spectral profiles of the lowest (−1,0)+1 Se1 and (0,1)0 De1 resonances display energy shifts in the meV range that depend on the pulse intensity. The results are explained by an effective two-level model based on calculated Rabi frequencies and decay rates.
High Resolution Multiphoton Spectroscopy by a Tunable Free-Electron-Laser Light / Žitnik, M., Mihelič, A., Bučar, K., Kavčič, M., Rubensson, J.E., Svanquist, M., Söderström, J., Feifel, R., Såthe, C., Ovcharenko, Y., Lyamayev, V., Mazza, T., Meyer, M., Simon, M., Journel, L., Lüning, J., Plekan, O., Coreno, M., Devetta, M., DI FRAIA, M., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 113:(2014), pp. 193201-193206. [10.1103/PhysRevLett.113.193201]
High Resolution Multiphoton Spectroscopy by a Tunable Free-Electron-Laser Light
DI FRAIA, MICHELE;
2014-01-01
Abstract
Seeded free electron lasers theoretically have the intensity, tunability, and resolution required for multiphoton spectroscopy of atomic and molecular species. Using the seeded free electron laser FERMI and a novel detection scheme, we have revealed the two-photon excitation spectra of dipole-forbidden doubly excited states in helium. The spectral profiles of the lowest (−1,0)+1 Se1 and (0,1)0 De1 resonances display energy shifts in the meV range that depend on the pulse intensity. The results are explained by an effective two-level model based on calculated Rabi frequencies and decay rates.Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
