Path: utzoo!mnetor!uunet!husc6!mit-eddie!mit-amt!joel
From: joel@mit-amt.MEDIA.MIT.EDU (joel s. kollin)
Newsgroups: sci.electronics
Subject: Re: HELP with LASRS and GRAPHICS!!!!
Message-ID: <2299@mit-amt.MEDIA.MIT.EDU>
Date: 14 Apr 88 03:41:47 GMT
References: <4333@cup.portal.com> <61700002@convex> <2335@cadnetix.COM>
Reply-To: joel@media-lab.MEDIA.MIT.EDU (joel s. kollin)
Organization: MIT Media Lab, Cambridge MA
Lines: 35

In article <2335@cadnetix.COM> rusty@cadnetix.COM (Rusty) writes:

>Well, I've got a strange thing I need: some sort of transducer
>to bounce a laser beam off of (in order to modulate it digitally).

>  want to modulate at as high a rate as possible.  (150mHz would 
>be great, but I'll settle for 500kHz, and 100kHz might work ok)
OA>
>  digital modulation (two states: laser on, laser off) to be effected by
>passing laser through what amounts to a (very thin) slit (ok, I'll
>give it away - I plan to pass the laser beam through a telescope),
>so beam deflection need not be too huge.

You can use an acousto-optic modulator to deflect the laser beam
and/or turn it off and on rapidly. Try Crystal Tech in Palo Alto.
Other companies and electro-optics technology can be found in optics
buyers guides (Photonics or Laser Focus).
I hope you're not thinking of laser tv.  It's been done.
Also, putting the modulated beam though a telescope will change the 
deflection angle.

>how about taking the cover off of a crystal and frequency modulating
>the crystal (very slightly, i realize)? OA 

Maybe.  Sounds like it's worth a shot to me.  If it works you should
write about it.

>The speed of liquid crystals is too slow, i think.  Anything else
>like LC I could use? (Power is only in the 2-5 mW range at the moment)

Doubtful. Why bother when you're using coherent light?  Acousto-optics
can modulate laser light up to 3 GHz.


joel