Ion formation in laser-irradiated cesium vapor

Abstract We study theoretically the formation of Cs + and Cs 2 + during cw laser radiation resonant with 6s-7p transition of Cs atomic vapor. This is done by numerically solving rate equations for the evolution of atomic state and electron populations. The results of calculations for the atomic and molecular ions density at different values of laser power clarified that the associative ionization and Penning ionization process play an important role for producing the Cs 2 + and Cs + , respectively, during the plasma formation. Also, the results showed that laser power of the order of 150 mW and 40–50 ns irradiation time are optimal in producing a fully ionized plasma.

[1]  Luc Barbier,et al.  Energy pooling process in rubidium vapour , 1983 .

[2]  A. Ralston.  A first course in numerical analysis , 1965 .

[3]  H. A. El‐Rahman,et al.  Modeling of laser-induced excitation and ionization in cesium atoms [rapid communication] , 2005 .

[4]  R. Measures,et al.  Laser interaction based on resonance saturation (LIBORS): an alternative to inverse bremsstrahlung for coupling laser energy into a plasma. , 1979, Applied optics.

[5]  T. B. Lucatorto,et al.  Efficient laser production of a Na/sup +/ ground-state plasma column: Absorption spectroscopy and photoionization measurement of Na/sup +/ , 1976 .

[6]  H. Kitaura,et al.  Processes of Multiphoton Ionization of Cs2 in the Wavelength Range 620–670 nm , 1993 .

[7]  A. Tam.  Quasiresonant laser‐produced plasma: An efficient mechanism for localized breakdown , 1980 .

[8]  Raymond M. Measures,et al.  Efficient laser ionization of sodium vapor—A possible explanation based on superelastic collisions and reduced ionization potential , 1977 .

[9]  P. Dhez,et al.  Direct Observation of Hot-Electron Spectra from Laser-Excited Sodium Vapor , 1982 .

[10]  B. Carré,et al.  Electron spectrometry study of associative and penning ionization in laser excited sodium vapor , 1984 .

[11]  R. Measures.  Selective Excitation Spectroscopy and Some Possible Applications , 1968 .

[12]  R. Measures.  Electron density and temperature elevation of a potassium seeded plasma by laser resonance pumping , 1970 .

[13]  P. Dreike,et al.  Production and diagnosis of a lithium anode plasma source for intense ion beam diodes , 1986 .

[14]  M. Mahmoud,et al.  Modelling of Collisional Ionization in Laser Excited Sodium Atoms , 1995 .

[15]  Wu,et al.  Ionization, excitation of high-lying atomic states, and molecular fluorescence in Cs vapor excited at lambda =455.7 and 459.4 nm. , 1985, Physical review. A, General physics.