Continuous-wave Lyman-α generation with solid-state lasers

Abstract

A coherent continuous-wave Lyman-alpha source based on four-wave sum-frequency mixing in mercury vapor has been realized with solid-state lasers. The third-order nonlinear susceptibility is enhanced by the 6(1)S - 7(1)S two-photon resonance and the near 6(1)S-6(3)P one-photon resonance. The phase matching curve for this four-wave mixing scheme is observed for the first time. In addition we investigate the two-photon enhancement of the Lyman-alpha yield and observe that the maxima of Lyman-alpha generation are shifted compared to the two-photon resonances of the different isotopes.

Photoionization pathways and thresholds in generation of Lyman-α radiation by resonant four-wave mixing in Kr-Ar mixture

“…32 By neglecting the contribution of Ar and estimating the value of χ (3) ≈ χ -36 cm 6 /erg (esu) 15 …”

“…Hydrogen L-α line radiation is required for efficient laser cooling via 1S-2P transition of hydrogen-like atoms. [2][3][4][5][6] Muonium L-α radiation can be used for generation of ultra-slow muons via the resonant excitation of low energy muoniums by 122.089 nm radiation followed by their ionization under 355 nm laser radiation. Ultra-slow positive muons can be used for local magnetic microprobes for nanoscale solid state physics, material and life sciences.…”

The Production and Study of Cold Antiprotons and Antihydrogen

“…Starting in the Hänsch Laboratory in Garching, and then moving to the Walz Laboratory in Mainz, our collaborators continue to improve a source of Lyman alpha radiation suitable for laser cooling and for 1s-2p spectrosocpy [46,47,48,49,50,51,52,53,54,55]. Four-wave mixing is used to generate continuous, coherent Lyman alpha radiation at 121.5 nm.…”

Continuous Lyman-alpha generation by four-wave mixing in mercury for laser cooling of antihydrogenThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010.

“…The blue laser at 408 nm establishes the two-photon resonance to the 6 1 S-7 1 S transition. Taken from [19]. provides a diagnostic tool for the two-photon-condition [15].…”

“…A residual background from the UV beam is eliminated by chopping the green laser at 1 Hz and subtracting the background from the Lymanalpha signal. We get 8000 Lyman-alpha counts/s with laser powers in the mercury cell of 180 mW at 254 nm, 200 mW at 408 nm and 260 mW at 546 nm and with a detuning to the 6 3 P level of the 202 Hg isotope of -400 GHz [19]. The overall detection efficiency of Lyman-alpha due to the absorption in the MgF 2 lens, the small mirror, the filters and the photomultiplier efficiency is 3 * 10 −5 .…”