Precious Metals? 1985 Spectra Physics Model 125 Gas Laser.

[BShan]

Ah, sorry. I was thinking about an other model from spectra physics. These resistors of the HeNe laser did look like the stability rods from a model 171 argon laser. In every of the three axis there where three ceramic rods with brass endcaps. The expansion of the ceramic and the brass did go to zero. So the resonator did get stabil.
Greetings from Germany
Harry

HeNe is like a neon sign tube, but fancy shaped; argon ion is a bit of a different beast. I only have seen 3 examples, but all of them were berylium ceramic, due to the extremely high heat their plasma generates. (brewster stems were still glass, IIRC, but the bulk of the tube was ceramic with heatsinking on it)

By the way, why are the mirrors gold-plated?
After all, silver and rhodium have the best reflective qualities.

From what I understand, different coatings are chosen based on wavelength. With a laser resonator, there is an additional requirement for one mirror, to be able to release a certain percentage of the desired light. This could possibly be a reason why they might choose a different coating.

Those mirrors are expensive, they might as well be coated in gold hah!