Dependence of the laser two-photon ionization process in solution on the laser pulse width.
The laser two-photon ionization process has been investigated using simultaneous irradiation of an UV beam and an IR beam. When the laser pulse width was 300 ps, it proceeded through a geminate pair state (a stepwise process), as indicated by the signal enhancement with simultaneous irradiation of the two laser beams. Although no signal enhancement was observed when the laser pulse width was 100 fs, and because molecules with no absorption at the laser wavelength showed an intense signal, the two-photon ionization excited by a femtosecond laser should proceed through a simultaneous two-photon process. The detection limit was quite susceptible to the laser fluctuations.
Ogawa
T
T
Department of Molecular Science and Technology, Kyushu University, Fukuoka, Japan.
Mizutani
M
M
Inoue
T
T