Distance measurement with heigh accuracy, a static project

Hello, I need to make a measurement of the distance to a liquid with very high precision, about 0.02-0.05 mm. The work distance is 2-4 mm, or any distance else without restriction. No movement, only distance measurement. I think about laser distance sensor, is it possible to make it with a low budget?

What liquid is it and is it coloured in any way ?
Is it the distance to the surface from above that you want to measure ?

Yes, it's frome above from the surface, I put a picture. Any liquid, also not coloured.

What is the actual application ?

The application of this project is:
The distance meter is fixed on an actuator with some other apparatus that measure some properties of the liquid (touchless).

How would you make such measurements without the use of a computer? What mechanism? How accurate and how repeatable and over what time frame do you need?

You will need a commercial instrument for that, and they are quite expensive. Search for "Laser distance sensor 0.01 mm".

Of course I connect a computer. For another apparatus that I use I need provide some exact distance or at lest some relative distance to liquid surface. The accuracy of 0.05 mm is ok for me. The response speed does not matter.

You still haven't told us what the liquid is.

So, the liquid could be anything

Ah, so cannot assume a capacitive sensor would work. A reflective IR sensor might be the way to go - the sort with light at 45 degrees and a line of sensors to catch the reflected beam.

any liquid, not colored