Thanks! The bulbs can be had for $40 a piece off Aliexpress: https://www.aliexpress.com/item/KLS-EKE ... 87725.htmlScarodactyl wrote:The bulb itself says "EKE" and "6fd"
The thorlabs label has a barcode, "osl2bir", and CHP125836 I assume none of this is useful.
The thorlabs stuff is on a sticker, it has been applied over a label that says "EKE 21v/150w/al"
The OSL1 arrived a minute before we had to leave for his lab, so we didn't realize it was nonfunctional until we got there. So we dug out a different 150w illuminator I had spotted to see if it would take the IR bulb. It wouldn't, but just for kicks we tried it out with its normal bulb.
It worked fine. From preliminary testing, significantly better than the fancy Oriel source they were using.
So, after all this searching and all the amazing help I've gotten here, it turns out their original light source was probably just whatever random illuminator was lying around, not something specialized at all. And was in fact pretty bad for this application.
I probably should have seen this coming. They were doing photography with a specialized IR c mount camera from the 90s, hooked up to a Zeiss opmi 1 using a 50/50 beamsplitter and SLR adapter, with the objective attached to a heavy helicoid itself attached to an x-y table. An insanely intricate setup, no part of which was the right tool for the job (even the specialized camera, which is so darned old it is way outperformed by a Canon EOS T6 with the hot mirror replaced by a 830nm bandpass).
Nevertheless, I already bought the bulb, and heck, if it's that much better than a normal 150w bulb they can run it at quite low voltage and it will last forever.
Other OSL1s were kind of expensive, but I realized that the OSL1 is identical to the Model 21AC by StockerYale. And better yet, with a bit of reading they also have a 21DC with extra light stability which would be good for their setup. So that is coming in, and hopefully we'll finally get to do a better test with everything lined up.
Thanks for the help everyone! I will give a (hopefully) final update when I have it.
That's a lot cheaper than Thorlabs' offerings. Lead time might be an issue but shipping cost shouldn't add too much if multiple units are purchased.