Locking the 405nm master laser will of course require an atomic reference. (see here for level structure)
This transition has a weaker cross section, as described here. In order to observe this line, we need to heat the typical vapour cell to a higher temperature:
Scanning the master laser piezo, we saw the characteristic saturated absorption peaks:
This had about the right width, given an 11MHz unresolved spread of 1-MHz-wide levels in the excited state.
So far these are averaged images — a single scan had worse signal-to-noise — so further improved optical density will be required.
page revision: 11, last edited: 06 Mar 2009 00:57