On 30 March 2013 19:50, Attila Kinali <[email protected]> wrote: > On Sat, 30 Mar 2013 18:43:03 +0000 > David Kirkby <[email protected]> wrote: > >> I would contact Hammamatsu Photonics >> >> http://www.hamamatsu.com
> This might be a good idea. Thanks! >> I played tricks during my Ph.D. of gain-modulating an APD with a step >> recovery diode. > You mean pulsing the bias voltage at about 7GHz and see whether > i can get a something out of that? I did not really have anything in mind specifically. I was just wondering if there was anything could do modulating the gain of a detector so forming a non-linear detector. I pulsed the voltage on an APD to buid a cross correlator. By doing that I was able to get better temporal resolution than the basic APD. Quick summary here: http://www.medphys.ucl.ac.uk/research/borl/research/phd_projects/davek_phd.htm Fulll thesis here http://www.medphys.ucl.ac.uk/research/borl/docs/dkirkby.pdf I have seen systems where one sinusoidally modulates the voltage of a photomultipler tube. You could do the same with an APD. Then it acts a a mixer. Essentially 1) Modulate laser at 100 MHz 2) Modlulate the APD bias voltage at 100.01 MHz 3) Detect light from laser on an APD. 4) Output of the APD is a sine wave at 10 kHz. > There has been a similar idea around, using a third laser that > is pulsed with the desired offset frequency. I was wondering if it could be done in more than one stage. A bit like a superhetrodyne receiver. I've had quite a few beers tonight (OK, I am ****ed) so my mind is not thinking too straight. >> Have you considered using a photomultiplier tube? I think there are >> some fast PMTs around, though perhaps not fast enough. 20 years I used >> to know what was state of the art in this area, but not any more. > > Not really. I am mostly looking at stuff i can easily get my hands on. > If possible without using ebay (other should be able to build the > system as well). PMTs are available new. Hamamatsu has almost 100 different types. http://www.hamamatsu.com/eu/en/product/category/3100/3003/index.html so there is no need to trawl ebay. Using PMTs you can easily get sub ns temporal response. Dave _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
