High-resolution measurements of the pressure broadening and shift of the rubidium $5{}^{2}S_{1∕2}\text{–}6{}^{2}P_{3∕2}$ line by argon and helium

We present results of the pressure broadening and shift of the rubidium $5s{}^{2}S_{1∕2}\text{–}6p{}^{2}P_{3∕2}$ (420.2 nm) spectral line by argon and helium buffer gases at pressures below 10 torr. High-resolution absorption measurements were performed with a single-mode external cavity diode laser, having 20-GHz tuning range and a linewidth of about 1 MHz. Pressure broadening and shift parameters of Lorentzian hyperfine components have been determined. We obtained the redshift of hyperfine spectral lines for He and the blueshift for Ar.

Figure 1

Absorption profile of the Rb $5{}^2{S}_{1∕2}\text{–}6{}^2{P}_{3∕2}$ line: circles, measured reference cell profile (the actual number of data points measured is reduced for clarity); full line, fit result (hyperfine lines forming the total absorption profile are also shown as dotted lines); vertical lines, relative intensities and frequency offsets of hyperfine lines.

Figure 2

Hyperfine structure of the Rb $5{}^2{S}_{1∕2}\text{–}6{}^2{P}_{3∕2}$ line.

Figure 3

The pressure broadening results of the Rb $5{}^2{S}_{1∕2}\text{–}6{}^2{P}_{3∕2}$ line in He and Ar (hyperfine line notation the same as in Fig. 1).

Figure 4

The frequency shift results of the Rb $5{}^2{S}_{1∕2}\text{–}6{}^2{P}_{3∕2}$ line in He and Ar (hyperfine line notation the same as in Fig. 1).