For sure! I didn't _quite_ want to get into the mechanics of it (assuming anyone who is interested would just take a peek at the wikipedia or any YT video).

But yes :)

Michelson interferometry is also used to measure the spatially-resolved velocity and magnetic field of the solar photosphere: https://en.wikipedia.org/wiki/Solar_Dynamics_Observatory -> Instruments

thanks !

oops! ran out of netlify credits. should be good now !

yeah I cheated a little bit, but

> Ok, time to confess: I did cheat a little in calling it the “cheapest” Michelson interferometer, since technically even this beam splitter is like 16 USD, but it is very possible to use a microscope slide instead at the cost of some contrast, which will net out to < 20 cents, even at pretty expensive per-unit prices.

:)

Not creep, but thermal expansion is definitely noticeable with interferometry: https://www.youtube.com/watch?v=vupIq4epCQA

Oh absolutely!

I would not actually use this for uhhh, repeatable measurements over any extended period of time!

(If that were the case, I'd recommend re-printing it in a slightly more stable material, or just CNC milling the mounts out of aluminum using some of the ~$1-2K aluminum desktop mills and using some aluminum extrusions as the base.)

Yes! Michelson interferometers are an amazing first lab experiment since it teaches you the basics of a bunch more techniques which are handy in more advanced experiments, while still having a satisfying outcome when done correctly (which is not as finicky as other experiments with less fun outcomes).

I wish that humans were not so easily duped into believing that things for which someone else uses the same name are really the same and things for which someone else uses different names are really different.

The Michelson–Morley experiment was indeed very important, but it has not proved in any way the non-existence of ether. It has just proved that the ether does not behave as it was previously supposed, i.e. like the materials with which humans are familiar.

It does not matter at all what names are used for it, one may choose to name it "ether", "vacuum", "electromagnetic field", "force field" or anything else, but all the modern physics, since James Clerk Maxwell and William Thomson, is built on the assumption that the space is not empty, but it is completely filled with something that mediates all the interactions between things.

Only before the middle of the 19th century, the dominant theories of physics assumed the existence of true vacuum. The existence of true vacuum is possible only in the theories based on action at a distance, like the Newtonian theory of gravity or the electromagnetic theory of Wilhelm Eduard Weber, but not in field-based theories, like the electromagnetic theory of Maxwell or the gravitational theory of Einstein.

It is rather shameful for physics that the main result of the Michelson-Morley experiment has been the replacement of the word "ether" by "vacuum", as if a change of name would change the thing to which the name is applied, instead of focusing on a better understanding of the properties of the thing for which the name is used.

With products from a vendor like Thor Labs, you're getting a lot of quality and knowledge built into the system. Mechanical engineers, electrical engineers, optical engineers... all of which means an edu kit like that will train a student to be useful in most grad research labs (which often build their systems out of thor labs components).

It sort of depends on what your goal is; personally, I live to see something expensive on Thorlabs, and make a simplified, less accurate, and far cheaper alternative in my home lab. But that's rarely how folks in labs do it- instead, they will focus on getting people to be useful for performing state of the art research, which usually depends on applying hundreds of years of experience to make some tiny marginal improvement, which frequently depends on having extremely precise and accurate gear.

Ironic isn't it, since Thorlabs brought down the cost of optical tooling and made components more accessible - they are the Amazon of optics and remain a cost leader.

I was a teaching assistant for freshman physics lab while in grad school, almost 40 years ago. My co-teachers were all theoreticians, so I bore the brunt of helping the students troubleshoot their setups.

There's a balance that has to be struck between: 1) Equipment that's so perfect that students learn nothing about the effort to get an experiment working. 2) Or so crappy that it's an obstacle to learning anything at all.

Also, the crappy-ness is multiplied by 30 for the number of setups needed for a class of 60 students, assuming they work in pairs.

Oh, the crappy oscilloscopes. They were cheap "student scopes" and their controls were worn out, so they behaved erratically. Since then I've met other people who took freshman physics lab, and they remember the "oscilloscope lab" with disgust.

ha, thanks!

that one has uhh substantially less drift for what it's worth, but reprinting in more stable material would help that a ton (and still be quite cheap!)

Thanks ! Still need to upload it to Printables etc. Maybe this will finally get my ass a bit more into gear.

what type of details would you like to see? happy to add more if helpful!

it’s an interferometer with like 5cm arms made for 3 bucks, it’s not made to be anything other than a basic demonstration !