Laser cooling of metastable He atoms in an inhomogeneous electric field

We have investigated laser cooling of metastable helium atoms by laser light at 389 nm using inhomogeneous electric fields for compensating the varying Doppler shift. As a result of the high polarizability of the upper cooling level, we were able to compensate for the large Doppler shift associated with the UV transition frequency and the high beam velocity with moderate field strengths. The method represents an alternate way to the standard Zeeman slowing technique. It is expected to be superior in applications, where high magnetic fields cannot be tolerated.