Open AccessTwo-photon resonant excitation of a doubly excited state in He atoms by high-harmonic pulses
Author(s) -
Taro Sekikawa,
Tatsuya Okamoto,
Eisuke Haraguchi,
Mikio Yamashita,
Takashi Nakajima
Publication year - 2008
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.16.021922
Subject(s) - excited state , atomic physics , excitation , high harmonic generation , polarization (electrochemistry) , photon , physics , harmonic , laser , ab initio , helium , optics , chemistry , quantum mechanics
We experimentally demonstrate a two-color two-photon resonant excitation of the doubly excited 2p2 1S state in helium atoms by the combination of 19th and 21st harmonic photons of a Ti:sapphire laser. Production of the 2p2 1S state is confirmed by the experimental observation that the electron emission from this state does not depend on the direction of harmonic polarization. Our ab-initio theoretical results through the solution of time-dependent Schrödinger equation are consistent with the experimental results and confirm the first successful production of a doubly excited state by high-harmonic pulses.