Optimization of sub-Doppler absorption contour in gas-dynamic beams

Abstract

The formation of the Doppler contour P (D)(?) of absorption lines upon the excitation of particles in the volume of a gas-dynamic beam by light propagating in a direction orthogonal (reduced) to the beam axis is analyzed. Integral representations of P (D)(?) are obtained for arbitrary relations between the nozzle outlet diameter D and the collimating aperture diameter B in the excitation region are obtained. An optimal configuration at which the reduced Doppler contour is the narrowest at a high density of beam particles is revealed to be B/D = 2

Measurement of the Absolute Photoionization Cross Section for the 5 P 3/2 State of 87 Rb in a Vapor Cell Magneto-optic Trap

“…Compared with the work of Gabbanini et al, [4] our number is also smaller. However, our data are consistent with the data of Klyucharev and Sepman, [13] considering that the data of Klyucharev and Sepman [13] are for an unresolved fine structure 5𝑝 state. The reason may be due to the fact that the ionizing laser intensity 𝐼 PI , employed by Dinneen et al [2] and Gabbanini et al [4] are not the average intensity 𝐼 PI of the ionization laser seen by the atoms in the MOT as employed in the our work.…”

“…4. Dinneen et al [2] and Gabbanini et al [4] have determined the absolute photoionization cross section for the 5𝑃 3/2 state of 87 Rb using atoms confined in a magneto-optical trap, 𝜎 PI = 13.6 ± 1.2 Mb at 413.1 nm and 𝜎 PI = 12.5 ± 1.1 Mb at 406.7 nm reported by Dinneen et al, [2] and 𝜎 PI = 14.8 ± 2.2 Mb at 476.5 nm reported by Gabbanini et al [4] Klyucharev and Sepman [13] reported 𝜎 PI = 9.8 Mb at 444.0 nm for an unresolved fine structure 5𝑝 state using hot atoms. It seems strange that the present photoionization cross section at 473 nm is smaller than that of Dinneen et al [2] at higher ionizing energy.…”

“…where 𝑃 is the power incident on the vacuum chamber and 𝑇 is the power transmission coefficient of the quartz window. [16] 400 420 440 460 480 500 520 6 In MOT, 1997 [4] Hot atoms, 1975 [13] In MOT, 1992 [2] Cross section (Mb) Wavelength (nm) Fig. 4.…”

Nonlinear Spectroscopy of Alkali Atoms in Cold Medium of Astrophysical Relevance

“…Solid lines in Figures 4 and 5 are plotted using Formula (19). Note that the theoretical results well describe the experimental data.…”

“…The second type represents a supersonic beam with v lg ≈ 1100 m/s [15] and a rather specific velocity distribution function [19]. An additional experimental possibility is represented by laser cooled atomic beams [20,21], which are characterized by small v lg around 12 m/s, which corresponds to the sub-thermal temperature interval lying below 1 K and practically negligible transversal velocity.…”