29 August, 2006

Odd Jobs

Traveling this week, Atlanta

On one of my few forays outside of “TV” I worked for an analytical instrument company that made some interesting lasers and laser based instruments (this is late 70’s) – with one YAG model you could get several watts of power – continuous, they also made a flash lamp pumped tunable dye laser that depending on frequency could give instantaneous peak power levels of a few thousand watts – one cool trick with that one was to tune the beam to a maximum absorption frequency of a specific ink and ‘zap’ that and only that ink away – the paper would twitch as you actually creating tiny explosions as the pulses would vaporize the ink.

This was before practical solid state lasers so they all involved glass tubes - either gas or a rare earth doped rod or liquid die – the smallest one I had was an alignment laser that was about the size of a large beer (think Fosters) and required AC power – and was just the thing to drive our cats crazy, I could have them climb half way up the wall trying to catch the beam – or hit the stop sign from a block a way – just as a car approached late at night.

Actually did some real science, we measured the distance to the moon a few times with pulsed laser, some of the Apollo landings left what are known as corner reflectors, they return a reflected image in (almost) any direction directly back to the source, we’d mount the laser on the scope and track the moon and (once we found one) measure the time between the outbound flash and the reflection – divide by the speed of light and there you go.

The tricky part is the ‘beam’ is only a few meters in diameter – at most, and each pulse is only 20 meters long or so, so hitting the reflector is as much luck as it is skil.l

It took several ‘negative results’ evenings before we got our first hit, once we had recalibrated the tracking and made minor adjustments to the scope mount we could get consistent returns once we found the reflector but finding them is difficult.

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