Date: Wed, 18 Aug 2010 10:45:46

Author: Sam Sampere

Subject: Re: Using a 40 mW laser safely?

Post:

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I should have my version from the shop on later today or tomorrow...

Sam

From: tap-l-owner@lists.ncsu.edu [mailto:tap-l-owner@lists.ncsu.edu] On Beh=
alf Of Cliff Bettis
Sent: Monday, August 16, 2010 9:23 AM
To: tap-l
Subject: [tap-l] Using a 40 mW laser safely?

I got one of the 40 mW (I measured its output with a power meter) at the P=
ortland meeting. I am in a new building and it's hard to adequately dim the=
lighting in the rooms especially the smaller classrooms, so I am trying to=
figure out how to do optics demonstrations under these circumstances. For =
diffraction, I can either use a TV camera and not have the students see the=
patterns directly or I can use a brighter source and show the diffraction =
patterns on the screen as usual. I decided to give the latter option a go a=
nd try to do it safely. My idea was to mount the 40 mW green laser in such =
a way that it would be very difficult to be exposed to the undiffracted bea=
m, so I mounted the laser on a heavy lathe style optical bench and mounted =
a diffraction wheel in front of it. The wheel is held on with a screw throu=
gh a slotted hole for alignment; the screw is held with a wing nut that is =
cotter pinned so that it can't be easily removed. The pattern are lovely, b=
ut I wonder what you think about the safety issue. Of course I can screen l=
ecturers who use this and make sure they are careful. When I can borrow the=
power meter again, I will measure the central maxima of the various patter=
ns.

What do you think?

Pictures at:

https://physicslearning2.colorado.edu/image/displayimage.php?album=3D4&pos=
=3D0

https://physicslearning2.colorado.edu/image/displayimage.php?album=3D4&pos=
=3D1

https://physicslearning2.colorado.edu/image/displayimage.php?album=3D4&pos=
=3D2

https://physicslearning2.colorado.edu/image/displayimage.php?album=3D4&pos=
=3D3

Cliff

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I should have my version=
from
the shop on later today or tomorrow…

=


Sam

=






From:
tap-l-owner@lists.ncsu.edu [mailto:tap-l-owner@lists.ncsu.edu] On Behalf=
Of Cliff
Bettis
Sent: Monday, August 16, 2010 9:23 AM
To: tap-l
Subject: [tap-l] Using a 40 mW laser safely?







I got one of the 40 mW (I measured its output wi=
th a
power meter) at the Portland meeting. I am in a new building and it’s
hard to adequately dim the lighting in the rooms especially the smaller
classrooms, so I am trying to figure out how to do optics demonstrations un=
der
these circumstances. For diffraction, I can either use a TV camera and not =
have
the students see the patterns directly or I can use a brighter source and s=
how
the diffraction patterns on the screen as usual. I decided to give the latt=
er
option a go and try to do it safely. My idea was to mount the 40 mW green l=
aser
in such a way that it would be very difficult to be exposed to the undiffra=
cted
beam, so I mounted the laser on a heavy lathe style optical bench and mount=
ed a
diffraction wheel in front of it. The wheel is held on with a screw through=
a
slotted hole for alignment; the screw is held with a wing nut that is cotte=
r
pinned so that it can’t be easily removed. The pattern are lovely, bu=
t I
wonder what you think about the safety issue. Of course I can screen lectur=
ers
who use this and make sure they are careful. When I can borrow the power me=
ter
again, I will measure the central maxima of the various patterns.



What do you think?



Pictures at:



https://physicslearning2.colorado.edu/image/displayimage.=
php?album=3D4&pos=3D0



https://physicslearning2.colorado.edu/image/displayimage.=
php?album=3D4&pos=3D1



https://physicslearning2.colorado.edu/image/displayimage.=
php?album=3D4&pos=3D2



https://physicslearning2.colorado.edu/image/displayimage.=
php?album=3D4&pos=3D3



Cliff







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