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PROFESSOR: We're now going to look
at another laser, the argon laser.
It's much more powerful than a helium-neon laser.
In fact, it can put out several watts and even
several tens of watts, principally, in the blue,
in the green, and also in the ultraviolet.
In this first demonstration, we're
going to take the output of this argon laser here,
and, without focusing it, we're going to send it
onto a piece of cardboard.
And we want to show you what happens.
Now, here you see the argon laser.
It puts out about 2 watts or so in the blue and green.
The blue is around 4880 angstroms,
the green is around 5145, and other weaker wavelengths,
both in the visible and also in the ultraviolet.
You can't see very much of the laser,
so what we're going to do is take the top off
so you can get a closer look at what's inside this laser.
Here is the argon laser without the top on.
It certainly looks very complicated.
But I'll try and help you along by identifying
some of the important features in the laser.
And we'll do this in close-up.
So first, let's zoom in to the left side of the laser,
where we see the mirror mount that holds
one of the laser mirrors.
So the mirror is held down there.
And then the air path between the mirror and the discharge
tube is sealed with bellows over here.
And here is, then, the beginning of the discharge tube.
Here you see the cathode--
the big cathode-- for this laser.
The bore of the tube is inside this magnet.
So you can't see it.
And then there is this magnet here
that provides a longitudinal magnetic field.
So here is the magnet.
And then the anode is located over here.
Now, because this is a powerful arc discharge,
both the bore and the magnet are water-cooled.
Over here, you see that the discharge tube
is terminated with a window at Brewster's angle.
And, finally, the second mirror is
mounted in this hole over here.
Now, we're going to turn the power on and look
at the output.
Now, the argon laser puts out a lot of power,
as I said, around 1 or 2 watts from this laser.
And one thing you don't want to do
is get in the way of the beam.
Now, here, we see a piece of cardboard
that's unlucky enough to be in the way of even
an unfocused beam.
So if we turn up the power in the argon laser,
you see what happens.
You see a nice hole burnt in and lots of smoke comes out.
And this is, remember, the unfocused beam.
We have about 1 watt of power.
And here is the hole we just burned
in the piece of cardboard.
Looks pretty bad.
And, remember, this is the unfocused argon beam.