[chmod775]

There's a lot of expertise with lithography around the world too (companies like Canon build lithography machines), but we're not talking the usual levels of it.

The EUV lasers ASML/TRUMPF builds don't even work the same way other "conventional" lasers would[1]. You physically can't get there by incrementally improving some existing process. Now I don't know how ZEISS makes mirrors that blown up to the size of a country would have imperfections smaller than a human hair, but I'm pretty sure it's no small feat either.

These companies invested decades and untold sums into this when few other companies even had incentive to attempt it themselves. Sure, other companies could eventually replace them, but you're not closing a 2-decade technology gap in an afternoon.

[1] It's a bit insane, really. Vaporizing falling droplets of tin with two laser pulses 100,000 times a second to get just the right wavelength? Here's a good video: https://www.youtube.com/watch?v=5Ge2RcvDlgw

[varjag]

It is impressive for sure, but still a lot of other things are. Mirror arrays on JWST, fusion ignition lasers. Diffraction limited optics aren't exactly last year development either: there's a host of other places across several countries who can match Zeiss for what is essentially bespoke builds.

[chmod775]

> there's a host of other places across several countries who can match Zeiss for what is essentially bespoke builds.

Ah yes. No development time involved here at all. They just built it. I don't know what ASML, TRUMPF, Zeiss, and occasionally the Fraunhofer Institute were mucking about for 25 years. Completely boring bespoke build. Bah. Could get it from anyone else by next week. Pick an off-the-shelf coating too and be done.

It's a wonder nobody else is taking a slice of those ~4 billion USD of revenue Zeiss is making off a bunch mirrors for lithography machines each year.