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Q: Quantenoptik
Q 17: Poster: Cooling and Trapping
Q 17.28: Poster
Wednesday, April 4, 2001, 12:30–15:00, AT2
Magneto-Optical Trapping of "Stark-Slowed" Metastable Helium Atoms — •R. Jung1, S. Gerlach1, R. Schumann2, U. Eichmann2, and G. von Oppen1 — 1TU-Berlin, Germany — 2Max-Born-Institut, Berlin, Germany
In this work we present the successful combination of laser cooling of metastable helium atoms in electric fields and trapping them using magnetic fields. Metastable He atoms from a LN2-cooled gas discharge-source are laser cooled at a wavelength of 389 nm (23 S1 | m |=1 → 33 P2 | m | = 2) inside a "Stark-slower", where the varying Doppler-shift is compensated by inhomogeneous electric fields[1]. Before the atoms enter the cooling-section, they are deflected and collimated by a single diode laser at 1083 nm. With final velocities lower than 20 m/s depending on the voltages applied to the Stark-slower the helium atoms are loaded into a standard magneto-optical trap (MOT). It consists of two coils outside the vacuum and a single trapping laser beam (λ=1083 nm). The lifetime of our trap is currently limited by a rather high background gas pressure of 1 · 10−8 mbar to τ ∼ 250 ms. We estimate a density inside the trap of 107 atoms/cm3. We will discuss possible experiments, in particular the transfer of metastable He atoms into an electric trap.
[1] R. Schumann et al. Phys. Rev A 59, 2120 (1999)