interferometro on line

[amtonio]

I have assembled a simple interferometer to verify the laser stability and it is correct, the stripes do not move, but if I mount it to verify the stability of the table then if they move, a while ago verify it and at that time it was correct

[amtonio]

the table is in a closed room, but I live in an attic, an eighth near the subway, they are not good conditions for holograms

[holomaker]

Good set up on the Fizeau interferometer !
What is you tables composition ?

[BobH]

The table being in a closed room is not good enough for the air stability you want. One needs to enclose the optical system in as small an enclosure as practical, with as many baffle cards inside as possible. You will be amazed at how much this simple thing improves stability.

[amtonio]

tables composition? I suppose you mean the table, it is a concrete block 120x80cm and 8cm high with a 1cm thick iron plate, all attached with 5 legs (a central one) on 5 rubber to insulate the floor, instead of gluing the iron iron on the concrete, rests on 12 10x10cm tires, distributed, it was done in case one day it had to be disassembled and not weigh so much, but I think it was a mistake, I send a photo

[amtonio]

here is the picture

[BobH]

If the concrete table slab touches the steel frame anywhere, the isolation from the tubes under it will be lost.

[amtonio]

I'm sorry the translation into English was not correct, I wanted to say that the iron plate rests on 12 rubber spread over the concrete block, I don't understand your answer

[holomaker]

I was always told to only isolate once, as if it’s done more, resonant frequencies can take over .....

[BobH]

Solid rubber does not isolate. Also, the isolation would need to be under the concrete slab, not under the steel, so that the weight of the concrete was above the isolation. Weight below the isolation does not help. The steel needs to be fully supported by the concrete. A layer of concrete patching compound with a sheet of plastic above it (to prevent glueing the steel to the concrete) will provide such support.

Rubber under the feet also does nothing but protect the floor.

If you must use that table as it is now, I would recommend only Denisyuk type exposure geometry.