The N resonance discussedd in:http://walsworth.physics.harvard.edu/publications/2005_Smallwood_HUBAThesis.pdf
May be a better bet than traditional CPT. Bruce On Saturday, 5 November 2016 12:17 PM, Magnus Danielson <mag...@rubidium.dyndns.org> wrote: Poul-Henning, On 11/05/2016 12:04 AM, Poul-Henning Kamp wrote: > -------- > In message <59dc074a-3a09-6315-29d4-6877c3bf7...@rubidium.dyndns.org>, Magnus > Danielson write > s: > >>> With respect to precision machining, that space has changed a lot >>> over the last five years, with precision CNC machines, factory >>> or home-built, dropping dramatically in price. >> >> You need to tune it regardless. > > First: Yes, but if you pick a sensible vibration mode for your > microwave resonance, that can be done with an screw-in endcap. Indeed. > Second: No, I would actually not need to tune it. > > Historically resonance cavities were used so that step/avalance > diode multipliers had enough power to excite them. Today we have > semiconductors which work at those frequencies. > > Later people kept the resonance, because it works well with low > power budgets in telecoms/milspec applications. > > But the resonanance leads to all sorts of trouble, including frequency > pulling, temperature sensitivities etc. > > We're neither space nor power constrained, we'd probably be > perfectly happy if the end result is 4U and 100W, so resonance > is not mandatory. Sure, but if you do have a cavity, as you was hinting at, tuning it is still needed for the cavity pull effect. > Third: A lot of the "everybody knows" about which atoms can be > used for active vs. passive atomic standards comes from the > state of the art electronics about 30 years ago. Sure, but some behaviors just remains there when still using such setups. > Using laser-pumping and modern semiconductors, it might actually > be possible to detect the 6.8GHz photons from the Rb. > > They won't be coherent photons, like in a Hydrogen maser, but we > don't need them to be, in fact that just causes the same exact > problems as the tuned cavity anyway, as long as we can measure > the frequency well enough. You can avoid the cavity using sidebands of the pumping laser and all that, yes I know. Active maser like the hydrogen would be possible naturally, but would require the resonator. A passive direct observation would also possible, but detection will be harder and then you would run into S/N issues. > (No, I havn't done the math on this, my wife has banned me from > starting any new projects until our house is finished.) Probably a wise thing. Cheers, Magnus _______________________________________________ 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. _______________________________________________ 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.