On Sun, 28 Apr 2013 17:50:06 +1200 Bruce Griffiths <bruce.griffi...@xtra.co.nz> wrote:
> Has anyone considered a laser pumped variant like: > http://tf.nist.gov/general/pdf/1009.pdf > > Apart from the ECDL laser (can be assembled using readily availalble > parts) it looks fairly straightforward. Considered, yes, tried, no. From what i've read sofar, this system has the problem of locking the laser wavelength onto the right absorbtion line. IIRC the linewidth of Rb in a vapor cell is a couple of 10kHz to a few 100kHz. Using an ECDL you get a laser linewidth of less than 1MHz easily, usally in the range of a few 100kHz and less. Ie. the laser would need to be kept on the absorption line with a stability of a couple of 100kHz at most. Using just a laser diode (without the external cavity) with its linewidth of >100MHz makes it actually a little bit easier to handle. But getting the laser to the right Rb absorption line and detecting whether it's off is still not solved. Most of the papers that i've read that do something similar use an additional vapor cell to determine the correct position of the laser. I'm quite sure that it could be done with a single vapor cell using some sophisticated control loop that steers both the 6.9Ghz signal and the laser wavelength, but i doubt it's easy. But then, i didn't have an in depth look at this. Attila Kinali -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.