P3D Re: Lasers

[roberts@xxxxxxxxxxxxxxxxx (John W Roberts)]

>Date: Tue, 10 Nov 1998 13:37:02 -0700
>From: Bob_Maxey@xxxxxxxxxxxx
>Subject: P3D Lasers

>I always err on the side of caution. As soon as one posts that it is safe
>to look at a laser at the exit, people will do just that, and with
>potential problems. 

Good point. That reminds me of when I was in high school, and took a
magnifying Fresnel lens (about 8 inches by 10 inches) to school. I showed it
to a fellow student while waiting at the bus stop, and his immediate reaction
(before I could react) was to try to look at the sun through it! Fortunately,
he didn't get it properly focused.

>Incidentally, the new green
>laser pointers offer a brighter (Apparent) light output with less actual
>output, as green is more easily seen than red.

That's the kind with the frequency doubler? (I saw an ad for one a year or two
ago, but haven't encountered them since.) Also the 630 nm red lasers are much
more visible for a given power output than the longer wavelength red lasers.

I've taken 3D photos with a laser scanned over a motionless scene in dark
surroundings - a very unusual effect. I suppose the spectral sensitivity of
the film would be an issue in choosing a laser for this purpose.

>Look, gang... do not be afraid of lasers, just use them with caution. I
>think it is important, that's all.

I agree completely. :-)

John R


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