Lasers - my $.25 worth ( thats 2 cents adjusted for inflation...)

Hi All;

I have been using a Nd-YAg 60W 1064Nm since 1990. At his point the
machine is a functional dinosaur.

It uses a full height enclosed 19" rack mount to house all the driver
subsystems. The rack is cooled by a water to air intercooler and the
De-ionized water is run thru a water to water intercooler. The main
computer is a Motorola 68000 ( 8 whole MHz! ) on a VME chassis with
2Mb ram... (Wow!)

The beam exiting the laser cavity is a 8x6mm ellisp - in some
applications we use a tunsten apature to trim the edges of the beam
to a perfect circle. The laser mirrors (99.5% and 100%) are
watercooled and are outside the laser cavity. There is a high speed
shutter before the 100% mirror which is used to modulate beam pulse
freq up to 32KHz.

The beam that exits the 99.5% mirror is run thru a beam expander -
there are many reasons for a beam expander but the most important one
is that you now have a up to 60Watts hitting within a 8mm circle.
This system uses mirrors on highspeed Galvos to direct the beam
within the lense marking field. - If the beam was not expanded these
mirrors would be burned thru in a few seconds.

The beam now goes thru the final lense group and at the proper focal
length is focused to a dot .1mm or less (about .0027") The galvos can
move the beam up to 999mm/sec.

I have a program that draws sheet music - and plays the tune as it
draws the notes. - People think thats neat. Its really simple, I am
hitting an object with energy - and can control the freq of the
impact - works like an adjustable tuning fork.

Back in 1990 the proper filtered safety glasses cost $640 each. (They
have dark green lenses resembling a #5 welding lense but with a much
more complex makeup - DON'T USE WELDING GOGGLES - THEY DO NOT PROVIDE
PROPER PROTECTION. )

I've worked with HeNe, Nd-YAg, and some diode lasers. I still
consider myself a rank amature... But I'm game if someone decides
Lasers need there own forum.

GAB