Multiphoton ionization dynamics of barium Rydberg states in intense femtosecond pulses

Journal Article · Thu Oct 01 04:00:00 EDT 1998 · Physical Review A

DOI:https://doi.org/10.1103/PhysRevA.58.3058· OSTI ID:659316

Tate, D A ^[1]; Gallagher, T F ^[2]

---

1. Department of Physics and Astronomy, Colby College, Waterville, Maine 04901 (United States)
2. Department of Physics, University of Virginia, Charlottesville, Virginia 22901 (United States)

We have investigated multiphoton ionization of Ba 6snl Rydberg states by intense 200-fs laser pulses. Specifically, we have excited Ba atoms to the 6sns and 6snd 15{lt}n{lt}{infinity} states using two nanosecond lasers. The atoms were then irradiated with the fs pulses produced by a mode-locked, regeneratively amplified Ti:sapphire laser that is stepwise-tunable between 790 and 850 nm. We have used both the fundamental light and the second harmonic (395{endash}425 nm) to investigate the ionization dynamics in these two wavelength regions. In contrast to previous experiments, in which laser pulses 5 ps or longer were used, our results indicate that excitation of Ba{sup +} Rydberg states and Ba{sup 2+} photoions is relatively insensitive to the femtosecond laser wavelength. In addition, we find that, as the Kepler orbital period of the Ba Rydberg electron becomes comparable to this very small laser pulse width, the inner electron ionization process no longer appears to be instantaneous to the outer electron, and the outer electron is not projected onto Ba{sup +} Rydberg states. {copyright} {ital 1998} {ital The American Physical Society}

• OSTI ID: 659316
• Journal Information: Physical Review A, Journal Name: Physical Review A Journal Issue: 4 Vol. 58; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BARIUM
BARIUM IONS
EXCITED STATES
INNER-SHELL IONIZATION
MULTI-PHOTON PROCESSES
PHOTOIONIZATION
PULSES
RYDBERG STATES