Date: Thu, 28 Mar 2002 10:40:36 -0800

Author: Steve Anderson

Subject: Re: illuminating laser beams

Post:

Reply to: Re: illuminating laser beams
for illuminating lasers, we have made a "micro-hazer" similar to the URL below that works well, close up, like in a demo.

http://www.netcomuk.co.uk/~wwl/smokegun.html

If you are willing to spend something, the pro lighting/DJ market sells a "Hazer" that has finer particulates than a fog machine.
Once the room is filled, at the top, you can turn it off and do beam shows for hours, + less stink.

http://www.seal-fla.com/fog/neutron.html

One technique i have used successfully, with plastic optics on a whiteboard, is to spread the beam into a line and come into the board at a slight angle. It then makes a line or "ray" on the white board, that focusses or internally reflects through the plastic lens or whatever. It can be seen in a lit room, with no fog. This is done by taping a 1/8" glass stirring rod (aka cylindrical lens) to the laser pointer/ HeNe.
To get multiple rays, I use a mirror and 30% beamsplitter, glued parallel with a 1/2" spacer and slightly staggered. This is at a 45 degree angle to the laser. By changing angle you can adjust the number of beams. The beamsplitter controls the intensity.
THEN put the stirring rod in front of these to get a demo "like in the book".

A stack of laser pointers with a cyl. lens on each one (to show on the board) works, too. I have more than one set up going at a time.

Sorry no web picture. please see ascii diagram below (view with a mono space font).

mirror beamsplitter or dialectric "green mirror"
/--/----->out3
/\ /
/--/----->out2
/\ /
laser----->/----->out1

s.anderson, P&A dept.
CSU Sonoma

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