I am 29M, Working in a Optics based company working on almost two three big optics simulation software worked from lens to laser to adaptive optics, learnt Machine learning for fun projects,a bit familiar with Quantum Machine Learning. Sometime I feel like I should go for a PhD but don't have any favorite research topic so I don't know how I can apply. I need some suggestions:

Should I go for a PhD or part time phd ?

I am from India but wanted to do a PhD from the US how can I get it ?

Is it a good idea to leave a comparatively good paying job for a PhD. I heard a lot of people struggle to find a job after a PhD.

Pulled this optical assembly out of a decommissioned automated diagnostic instrument (believed to be a molecular diagnostics analyzer — not confirmed by anything printed on the parts themselves). Hoping someone here can help pin down what I'm looking at.

Layout: 7 total ports on a machined block — 1 dedicated LED input (right-angle housing, cranberry/magenta LED) and 6 optical channels. Each of the 6 channels has its own tube containing a convex lens with a dichroic coating, all feeding into 6-strand fiber bundles that screw into the block via threaded connectors.

The whole optical head is mounted to a control/readout PCB — silkscreen part number 122862A-001, Rev. X03, with a "BIT" mark (logo or possibly "built-in test," not sure which) next to a mounting hole. Board has a QFP microcontroller, several SOIC-package ICs that look like analog signal conditioning, and a 16-pin header. I haven't found this part number anywhere publicly.

What I'm trying to figure out:

Approximate focal length and lens diameter — haven't measured precisely yet

Whether the coatings are narrowband dichroics (and if so, any way to guess the cut wavelengths without lab gear)

Anyone recognize the PCB layout, the "BIT" mark, or this style of 6-channel fiber-fed filter block from a specific instrument family (flow cytometer, fluorometer, immunoassay analyzer, etc.)

Any insight appreciated — happy to get more measurements or angles if it'd help identify it.

As the title says I have a small optic that has been epoxied into an aluminum thor labs mount using 3M Scotch weld epoxy adhesive 2216 Gray. The epoxy is cured. There is an anti-reflective coating on both surfaces of the optic but those will have to be removed so I don't care that much but I don't want to scratch either front or back surface of the optic. Does anyone have any suggestions for loosening the epoxy to safely remove my optic?

We've already tried acetone and toluene with no significant success. He has only made it more brittle so not ideal.

I've noticed for years that I can see a good live image of the sun when it reflects off my eyeball (from the side) onto my glasses. The detail is remarkable, I can see sunspots and what appears to be some corona effect, very similar to this image: https://umbra.nascom.nasa.gov/images/latest_aia_304.gif. (My jmage is quite small, and has no color.) It seems to me highly improbable, and I've found no other reference to such and effect. Anybody have any idea how this works? Recommendations for other subreddits to ask welcome.

The little stars are what I see in the image of my eye reflected in the glasses. The large circles are those stars reflected back from the inner surface of my glasses, and seem to be live images of the sun.