Seems to me if one is capable of constructing a ruby laser then a thullium laser could be constructed.This is very interesting; I'm surprised that there are no replies yet. I'll start.
The original research article is not pay-walled and can be found here (just click on the pdf link):
One technique uses scanning but reproducing this looks to be too expensive for hobbyists. The laser used are 1.9072 μm thulium-based fiber laser from IPG Photonics. Here is a link to their low power systems in this range, as is typical, costs are not given on the company website: https://www.ipgphotonics.com/en/products/lasers/low-power-cw-fiber-lasers#[1-9-2-05-micron]
Since one of the techniques involves scanning, if it were possible to obtain lasers like these, it seems to me that this would be fun to play with. Does anyone here have any idea what these kinds of lasers cost? Are there other (cheaper) laser systems that operate at 1907.2 nm that could be used as an alternative? Are there any diodes in this range?