Buffer gas

About: Buffer gas is a research topic. Over the lifetime, 3565 publications have been published within this topic receiving 47283 citations.

Realization of Coherent Optically Dense Media via Buffer-Gas Cooling

Abstract: We demonstrate that buffer-gas cooling combined with laser ablation can be used to create coherent optical media with high optical depth and low Doppler broadening that offers metastable states with low collisional and motional decoherence. Demonstration of this generic technique opens pathways to coherent optics with a large variety of atoms and molecules. We use helium buffer gas to cool $^{87}\mathrm{Rb}$ atoms to below $7\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ and slow atom diffusion to the walls. Electromagnetically induced transparency in this medium allows for 50% transmission in a medium with initial optical depth $Dg70$ and for slow pulse propagation with large delay-bandwidth products. In the high-$D$ regime, we observe high-contrast spectrum oscillations due to efficient four-wave mixing.

Observation of anomalous light-induced drift

Abstract: In a two-component gas consisting of light-absorbing particles immersed in a buffer gas, velocity-selective excitation combined with a state-dependent kinetic collision frequency results in light-induced drift. Standard theory predicts that the drift velocity as a function of frequency detuning should have a dispersion-curve-like behavior. This was indeed found experimentally for the molecular species studied so far. We report a dramatic deviation from this behavior for C{sub 2}H{sub 4}, excited into its {nu}{sub 7} vibrational mode by a CO{sub 2} laser, with Kr as a buffer gas. The extent of the deviation is found to depend strongly upon the rotational sublevels involved. A possible explanation in terms of a three-level model is attempted but found to be unlikely.

Low wattage fluorescent lamp

Abstract: A low-wattage mercury lamp (figure 1) is provided for use with existing 110V high frequency electronic ballasts. The lamp has a discharge sustain fill (22) of mercury and an inert gas mixture of krypton and argon that does not require a starting aid. The phosphor layer (16) has a coating weight of 2.0-3.9 mg/cm2.