Re: [Phys-L] feedback control for zero output

[Ludwik Kowalski <kowalskil@mail.montclair.edu>]

That would be trivial, if light was coming out of "one port" as a parallel beam, not touching the diaphragm. Just place the "another port " (also a large diaphragm) on the path of the beam, close to the first one. I suspect you want to accomplish something very different.

Ludwik Kowalski

http://csam.montclair.edu/~kowalski/life/intro.html 

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On Aug 7, 2013, at 4:55 PM, Carl Mungan wrote:

> I have a device I'm trying to construct in which I want to null all the
> light coming out one port and have it all go out another port. However, the
> light is very intense, so I don't want to sample the "on" port. I'd rather
> have a detector monitoring the "off" port to use as the feedback signal.
> But the problem is "off" isn't a very good condition to monitor. (It's very
> subject to noise.)
>
> Is there a way to build a feedback control using a null as input? I tried
> googling various terms and couldn't find a good starting point to get me
> thinking about this stuff productively.
>
> Any help would be greatly appreciated. -Carl
>
> -- 
> Carl E Mungan, Assoc Prof of Physics  410-293-6680 (O) -3729 (F)
> Naval Academy Stop 9c, 572C Holloway Rd, Annapolis MD 21402-1363
> mailto:mungan@usna.edu     http://usna.edu/Users/physics/mungan/
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