On Sat, 30 Mar 2013 18:43:03 +0000 David Kirkby <david.kir...@onetel.net> wrote:
> I would contact Hammamatsu Photonics > > http://www.hamamatsu.com > > and see if they can help. They might havae something in development, > that is not on the web site. If you are in a uni, they might be > especially helpful - they paid my salary for a couple of years as a > post-doc. This might be a good idea. Thanks! > I played tricks during my Ph.D. of gain-modulating an APD with a step > recovery diode. I was wondering if there is anything one could do to > gain modulate one at 7 GHz, but I can't think how one could achieve > anything useful by changing the gain, but it might be worth thinking > about. I'm just trying to "think out of the box" - I can't actually > see how it would help. You mean pulsing the bias voltage at about 7GHz and see whether i can get a something out of that? There has been a similar idea around, using a third laser that is pulsed with the desired offset frequency. Using this and the non-linear intensity response of the photodiode one can get a low frequency correlation signal out of the system. A Japanese group did something like this to acheive offset frequencies of 160GHz[1] and later of 1THz[2]. In [3] Aljunid describes how to build such a correlator for fs pulses using a simple LED. (yes, i came across some really weird stuff when i started digging into this) > 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). Attila Kinali [1] "External Synchronization of 160-GHz Optical Beat Signal by Optical Phase-Locked Loop Technique" by Shigehiro et al, 2006 http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4012083 [2] "Development of an Optical Phase-Locked Loop for 1-THz Optical Beat Signal Generation" by Shigehiro et al, 2008 http://www.furukawa.co.jp/review/fr033/fr33_02.pdf [3] "Optical Autocorrelation using Non-Linearity in a Simple Photodiode" by Aljunid, 2007 http://qolah.org/thesis/thesis-syed.pdf -- 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.