Effects of a laser pulse photoionizing an effectively excited three-level atom on the ion yield

three-step, three-photon scheme of 6'So (0 cm-I) -+ 6 3 P ~ (17992.008 cm-') --c (;, :)z4f1'6s26p (35 196.98 cm-') + autoionization state (52353 cm-') is chosen to examine the selective photoionization of 168yb. The Maxwell-Bloch equation is numerically solved, where the interacting laser pulses me supposed to be mllinear and resonam with the transition lines of '"Yb, and the effects of Doppler broadening and laser bandwidth are incorporated. Firstly. the thin medium dynamics are examined to determine the optimal energy of laser pulses for the selective photoionization of layb. and to determine Yb isotopes which have a large influence on the excitation of I6%.Secondly, the thick medium dynamics are investigated, resulting in the fact that the laser pulse for tke first transition is prominently deformed due to the near-resonant interaction with '"Yb and "%, and t h e ion yield along the propagatian of the laser beam is strongly dependent on the initial energy of pulse for the first h'ansition and the time-delay between input pulses.

Section: Population Dynamics In the Thin Mediumsupporting

confidence: 64%

Selective photoionization of¹⁶⁸Yb in a three-level atomic medium by the collinear propagation of laser pulses

Choe

Rhee

Lee

et al. 1995

“…One of the reasons for the utilization of such a scheme is that the spectroscopic parameters (Krynetskii et al 1991), lifetimes of the excited states (Krynetskii et al 1991, Blagoev and Komarovskii 1994, Bowers et al 1996, dipole moments of the transitions (Burshtein et al 1974) and energy levels (Martin 1978) have been thoroughly studied. The isotope shifts of all the Yb isotopes and hyperfine structure (hfs) constants of the odd isotopes have been accurately measured for the 4f 14 6s 2 1 S 0 -4f 14 6s6p 3 P o 1 (555.648 nm) transition by several groups (Broadhurst et al 1974, Clark et al 1979, Jin et al 1991, van Wijngaarden and Li 1994 and for the 4f 14 6s6p 3 P o 1 -4f 13 6s 2 6p ( 7 2 , 3 2 ) 2 (581.027 nm) transition by Choe et al (1995a) and Borisov et al (1996). The limitation of this photoionization scheme is that the isotopic selectivities that can be obtained for the 4f 14 6s 2 1 S 0 -4f 14 6s6p 3 P o 1 (555.648 nm) transition are rather small.…”

Section: Introductionmentioning

confidence: 98%

“…Isotope-selective excitation/ionization using laser atomic beam spectroscopy (Letokhov 1987) has become a potential tool for studying the laser isotope separation processes. There has been genuine interest for studying the isotopic selectivities of lanthanides such as Gd (Santala et al 1994, Suryanarayana and, Yb (Choe et al 1995a, Borisov et al 1996 and La Shaw 1995, Sankari and because of their economic value. Diode-laser initiated resonance ionization mass spectrometry has been used (Shaw et al 1989) for isotope-selective studies of low-abundant 138 La isotope.…”

Section: Introductionmentioning

confidence: 99%

“…Isotope-selective photoionization of the 168 Yb isotope is rather complicated because of the hyperfine structure of the odd isotopes which have a large spectral overlap with the 168 Yb isotope. Mishin and his co-workers (Choe et al 1995a, Borisov et al 1996 have extensively studied threecolour, three-step, three-photon ionization schemes for isotope-selective photoionization of the 168 Yb isotope: 4f 14 6s 2 1 S 0 (0 cm −1 ) → 4f 14 6s6p 3 P o 1 (17 992.007 cm −1 ) → 4f 13 6s 2 6p( 72 , 3 2 ) 2 (35 196.98 cm −1 ) → autoionization (AI) state (52 353 cm −1 ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Studies on the isotope selective photoionization of the low-abundant isotope

Sankari

Suryanarayana

1998

The efficiency of the two photoionization schemes scheme 1: 4f 14 6s 2 1 S 0 (0 cm −1 ) 555.648 nm −→ 4f 14 6s6p 3 P o 1 (17 992.007 cm −1 ) 581.027 nm −→ 4f 13 6s 2 6p( 7 2 , 3 2 ) 2 (35 196.98 cm −1 ) 582.79 nm −→ autoionization state (52 353 cm −1 ) → Yb + and scheme 2: 4f 14 6s 2 1 S 0 (0 cm −1 ) 398.8 nm −→ 4f 14 6s6p 1 P o 1 (25 068.222 cm −1 ) <394 nm−→ Yb + has been studied by a spectral simulation approach for the isotope-selective excitation of the 168 Yb isotope. Isotopic selectivities have been computed for 4f 14 6s 2 1 S 0 -4f 14 6s6p 3 P o 1 (555.648 nm), 3 P o 1 -( 7 2 , 3 2 ) 2 (581.027 nm) and 4f 14 6s 2 1 S 0 -4f 14 6s6p 1 P o 1 (398.8 nm) transitions for various laser bandwidths of the excitation lasers. The degree of enrichment of the lowabundant 168 Yb isotope has been computed using the obtained isotopic selectivity values. Results obtained for scheme 1 are in good agreement with the results reported earlier. The abundance of 168 Yb isotope has been computed for various laser linewidths of the excitation laser and Doppler widths for scheme 2. Comparison of the two photoionization schemes for isotope-selective photoionization of the 168 Yb isotope has been made. The present computational method has been examined for computation of degree of enrichment for the photoionization schemes under consideration.

“…However, fixed detunings, if a slightly incomplete inversion is allowed, will allow an easier experimental approach. In previous studies, the optimal detunings for the different Rabi frequencies could only be determined numerically, based on the formulae of the optimal detunings in the case of square pulses (Choe et al 1995). Therefore, the main purpose of our study is to suggest a method to obtain constant optimal detunings which cause optimal inversion in the case of different Rabi frequencies and present some values of the optimal detunings found by using the optimal detuning parameter.…”

Section: Introductionmentioning

confidence: 99%

Laser frequency detunings for complete inversion and optimal inversion of a three-level atom by arbitrary Rabi frequencies

Choe¹,

Lee²,

Moon³

et al. 1999

Self Cite

In a three-level atom interacting with nondelayed laser pulses, the inversion dynamics is studied to examine the detunings of the laser frequencies. When two Rabi frequencies are unequal, we show the interesting fact that complete inversion occurs if chirping is used, which causes the effective detuning of a two-photon resonance line to be zero. Because fixed optimal detunings allow an easier experimental approach, it is useful to find a method for obtaining the optimal detunings for realistic ratios of two Rabi frequencies. Using these optimal detunings, the process turns out to be a diadiabatic transition from investigation of the eigenvector and Bloch vector motions, whose behaviours are compared with their behaviour in the case of complete inversion.