The principle of LWI is to cancel the absorption at the laser transition by coherent excitation of adjacent transitions so that only a few excited atoms are sufficient for lasing. Whilst there is no more absorption for coherent light, the laser transition can still be pumped by an incoherent light source like a gas discharge lamp.
Until now there has been no LWI scheme where the laser transition had a significantly shorter wavelength than the lasers used to build up the coherence.
In our LWI experiment, we use a 4-level-scheme in mercury with a laser transition at 253.7 nm as described in [1]. For this scheme a strong driving laser at 435.6 nm, a weak driving laser at 546.1 nm and an incoherent repump at 404.7 nm are required.
[1] E. S. Fry, M. D. Lukin, T. Walther, and G. R. Welch, “Four-level atomic coherence and cw vuv lasers,” Optics Communications 179, 499 – 504 (2000). |
Prof. Dr. Thomas Walther
Laser und Quantenoptik
Institut für Angewandte Physik
Fachbereich 05 - Physik
Technische Universität Darmstadt
Schlossgartenstr. 7
D-64289 Darmstadt
+49 6151 16-20831 (Sekretariat)
+49 6151 16-20834 (Fax)
Thomas.Walther@physik.tu-...
03.04.19