Re: [time-nuts] LED instead of discharge lamp for Rb vapor cell standards

Hi, On 02/22/2018 02:53 PM, Bob kb8tq wrote: > Hi > > >> On Feb 22, 2018, at 8:22 AM, Attila Kinali wrote: >> >> On Wed, 21 Feb 2018 18:10:17 + >> "Poul-Henning Kamp" wrote: >> So the Rb85 "notch" filter might not get rid of all the unwanted

Re: [time-nuts] LED instead of discharge lamp for Rb vapor cell standards

Hi > On Feb 22, 2018, at 8:22 AM, Attila Kinali wrote: > > On Wed, 21 Feb 2018 18:10:17 + > "Poul-Henning Kamp" wrote: > >>> So the Rb85 "notch" filter might not get rid of all the unwanted light >>> and some of this might depopulate the excited

Re: [time-nuts] LED instead of discharge lamp for Rb vapor cell standards

On Wed, 21 Feb 2018 18:10:17 + "Poul-Henning Kamp" wrote: > >So the Rb85 "notch" filter might not get rid of all the unwanted light > >and some of this might depopulate the excited state of the Rb87 > >that are in the RF cavity. > > I have a hard time seeing how you can

Re: [time-nuts] LED instead of discharge lamp for Rb vapor cell standards

Hi There are a number of papers on LED / Laser excitation of Rb cells (and other gas cells). They go back quite a ways. The gotcha (as pointed out in PHK’s post) is that you need to stabilize the LED source. Doing that is a bit complex. Doing that so that the result beats a gas lamp is a bit

Re: [time-nuts] LED instead of discharge lamp for Rb vapor cell standards

In message <20180221184928.1c9b4c3a4d2e762970b5b...@kinali.ch>, Attila Kinali w rites: >So the Rb85 "notch" filter might not get rid of all the unwanted light >and some of this might depopulate the excited state of the Rb87 >that are in the RF cavity. I have a hard time seeing how you

Re: [time-nuts] LED instead of discharge lamp for Rb vapor cell standards

Attila I haven't tried that and I suspect the lines are important because that establishes the reference. Now I would also suggest that an experiment like you suggest be tried on a FRS-XXX cheapy Rb. Easily dis-assembled and can be re-assembled back with the lamp. No harm. Paul WB8TSL On Wed, Feb

[time-nuts] LED instead of discharge lamp for Rb vapor cell standards

Moin, Has anyone ever tried using a LED instead of a discharge lamp for Rb standards? There are quite a few and very cheap 780nm IR LEDs available. They usually have a line width in the order of 20nm to 50nm (FWHM). This means that they still need the Rb85 filter, but they would not produce all