Re: [time-nuts] laser as clock source

(replying to myself here) ... one other way to use a laser as a clock is to use a pulsed laser like a frequency comb, where the pulse period is locked to an external reference like a Cs. A system like this has been used for synchronization along a particle accelerator beamline, to give one

Re: [time-nuts] laser as clock source

Dear Ilia Emission of light is a quantum mechanical process. It is fundamentally statistical in nature and as someone commented earlier, makes a good random number generator. Here's one, for example: http://www.nature.com/articles/srep10214 If you attenuate any light source, lasers included, to

Re: [time-nuts] laser as clock source

No, laser photon count statistics are Poissonian. There are fluctuations in photon detection rate. The distribution of photon energies is narrow (for a single spatial and temporal mode laser). Bruce On Saturday, 7 May 2016 6:01 PM, Ilia Platone wrote: Wait... no

Re: [time-nuts] laser as clock source

Wait... no telescopes, very close distances... only a laser, with a photon limiter like a dark window, "close" like 10mm or so... just the space required for the laser optics plus the "limiter", and a photon counting detector that can be an APD or a PMT, it depends on the size required and

Re: [time-nuts] laser as clock source

On 5/5/16 12:22 PM, Hal Murray wrote: jim...@earthlink.net said: Well, in deep space optical comm, we send many photons with a laser, and we use pulse position modulation at the receiver detecting single photons (or "few photons"), by which we can send "many bits/photon" (e.g. if you have

Re: [time-nuts] laser as clock source

Hi, Indeed, as the laser is damped down, it will measure the AM noise more than anything else. Cheers, Magnus On 05/05/2016 01:39 PM, Bob Camp wrote: Hi At least back “a few” years ago … counting photons was a pretty good way to generate random numbers. It’s sort of like looking at

Re: [time-nuts] laser as clock source

jim...@earthlink.net said: > Well, in deep space optical comm, we send many photons with a laser, and we > use pulse position modulation at the receiver detecting single photons (or > "few photons"), by which we can send "many bits/photon" (e.g. if you have > 256 possible time slots in which

Re: [time-nuts] laser as clock source

On 5/5/16 3:16 AM, Poul-Henning Kamp wrote: In message <11200676-5915-28f2-d6f6-c69b11fd9...@iliaplatone.com>, Ilia Platone writes: Is it possible to use the photon flux of a laser as clock source using a sensor in photon-counting mode? As far as I know: Photon-counters only work

Re: [time-nuts] laser as clock source

If it were frequency stabilised to  the required degree and the detector had attosecond response. Or in practice if one uses  stabilised laser frequency combs. Bruce On Thursday, 5 May 2016 10:14 PM, Ilia Platone wrote: Is it possible to use the photon flux of a

Re: [time-nuts] laser as clock source

Hi At least back “a few” years ago … counting photons was a pretty good way to generate random numbers. It’s sort of like looking at current flow. The discrete nature of the process shows up if you look carefully enough. Bob > On May 5, 2016, at 12:55 AM, Ilia Platone

Re: [time-nuts] laser as clock source

In message <11200676-5915-28f2-d6f6-c69b11fd9...@iliaplatone.com>, Ilia Platone writes: >Is it possible to use the photon flux of a laser as clock source using a >sensor in photon-counting mode? As far as I know: Photon-counters only work at low rate of photons and lasers only work

Re: [time-nuts] laser as clock source

Ilia, On 05/05/2016 06:55 AM, Ilia Platone wrote: Is it possible to use the photon flux of a laser as clock source using a sensor in photon-counting mode? Or the photon rate will be chaotic and unstable (as I think but wanted to know)? There will be noise. Lots of it. Feel free to measure

[time-nuts] laser as clock source

Is it possible to use the photon flux of a laser as clock source using a sensor in photon-counting mode? Or the photon rate will be chaotic and unstable (as I think but wanted to know)? Regards, Ilia. -- Ilia Platone via Ferrara 54 47841 Cattolica (RN), Italy Cell +39 349 1075999