Self-focussing in a vapour of two-state atoms

Sucharita Sinha, K. Dasgupta, K. G. Manohar +2 more

Leslie Pendrill, M Pettersson, Ulf L. Österberg

A comparison of the spectral variation of ions, produced in a thermal vapour of potassium irradiated with resonant laser light, with the absorption spectral profile of the vapour confirms earlier conclusions that ionization upon collision of two excited atoms in the 4P state is the dominant ionization process, at least in the spectral line wings. No evidence of contributions from supereleastically-heated electrons to the ionization is found. Strong spatial distortions of the laser beam transmitted by the vapour (self-focussing and anomalous conical emission) are observed and discussed in relation to the ion production.

Marcos Oriá, D. Blöch, Martine Chevrollier +2 more

D. Dubbers, H.‐J. Stöckmann

Castellanos, L. M., Lopez, F. E.

A theoretical description in terms of the coherence propagation is given for self-focussing. The concept of coherence length is defined in terms of free, self-focussing propagation giving results in accordance with well known experimental criteria for the laser. Extension of the method is given for an Atom Laser showing good results in agreement with recents numerical results of Trippenbach et. al.: J. Phys. B:At. Mol. Opt. Phys. 33, 47-54 (2000).

Geoff Campbell, Christopher Healey, J. Appel +3 more

Recently, the possibility of generating squeezed vacuum states via polarization self‐rotation in hot atomic vapour has been debated. We present experimental results confirming that vacuum squeezed states can be generated using this method.