[Laser] looking for ideas on amplifying RS laser pointer

Thu, 15 Aug 2002 20:35:34 -0400 (EDT)

	Dear People:

	One of the simpler light collection systems for laser or other
optical free space comm is to acquire the parabolic reflectors used in the
hand help "one million candle power" spot lights that are often equipped
to plug in auto or truck cigarette lighter socket.

	Observe EXACTLY where the FILAMENT of the lamp is....

	Remove the lamp and place the photo detector there....

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	A little more complicated:
	OR whatever set up you are using to couple OUT from the laser.

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	Some of these are 6 inches and provide gain of 1,000 to 7,500
		optical for reception.

	Careful placement of the detector and fine "tuning" thereof
  may sometimes be accomplished by fixing the detector on a long-ish rigid
stem and clamping this to an X-Y-Z set up from a microscope stage... or
hand made from wood and long machine screws ..... with a test laser, maybe
100 yards out ... or close to effective 'infinity' you can then move the
support for the detector so you can visually see the maximum illumination
on the transduction element.   A carrier tone on the test laser may help.

	sometimes a circle of mylar "drafting vellum"... which is, of
course not vellum, but plastic, can be used, frosted side outward, as an
integrator to reduce the criticallity of laser alignment... 

	The frosted side offers poor reflection ...and the shiny side
...on the inside of the set up... promotes multiple internal reflections
so thereby "trapping" a small amount of light that may have been lost due
to specular reflection....
	sort of "The 2 Cent Anti Reflection" surface treatment ... this
can up you another few hundred, depending on how off the set up may be.

	"just hit the circle" and then the first surface lamp parabola
does the rest of your legwork.... uh... eyework.

On Thu, 15 Aug 2002, Chuck Houghton wrote:

> Jeffrey have a large file using a LED transverter with optical receiver for
> communications, We have replaced the led with a pocket laser pen and use the
> same basic circuit to modulate it as the LED. With the pocket laser have use
> it for wbfm , psk-31 and slow scan computer generated video over a 15 mile
> path full duplex. If you can handle the large file will send it to you in Word
> format with photos and descriptions how to build. Let me know if you want
> large file.
> 
> Have even come up with another scheme we are working on using a large aperture
> lense with a 1 1/2 inch hole cut for cassigranian (spelling) objective with
> laser located in hole under development. using same electronics but simpler
> focusing scheme.
> 
> JEFFREY MICHAEL KENYON wrote:
> 
> > Hi everyone.  I have finally found my older Radio Shack Laser Pointer, and
> > it is the 300 foot pointer that is pen shaped.
> >         I would like to amplify it.  Any ideas?  Also, I am looking for
> > ways to communicate using lasers, and am in Grosse Pointe, Michigan just
> > outside of Detroit.  Any help would be appreciated, and thanks in advance.
> >
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> 
> 
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