Re: [ATM] lurie-houghton progress

[Mike Lockwood <melockwo@uiuc.edu>]

Guy,

Guy Brandenburg wrote:
> Once the long-FL concave surface is decent, we'll have
> to do some trial and error to figure out what to do
> with the convex surface to get it to match the concave
> surface, as shown by straight interference fringes
> under the monochromatic light source. Anybody have
> practical experience with that?

Yes, I do.  Your test setup is already constructed, right?  What 
questions do you have?

> Then we put the convex one (**carefully**) on top of
> the convex one in our monochromatic light box, so that
> we could look at the interference fringes. The fringes
> were almost perfectly straight as well! Again, we were
> very, very pleased.

I assume that's convex one on top of the conCAVE one.  ;)
Can you take a picture of the fringes and post it?  I would be very 
surprised if you had less than a few fringes after polishing, since 
both surfaces generally change curvature while being polished, and 
usually in different directions.  How many fringes were you viewing 
when you saw nearly straight fringes?

> The glass for a LH doesn't have to be expensive at
> all. Plate glass would work fine, as long as it
> doesn't have strain. The only thing is that it's not
> terribly transparent.

Is plate glass quite homogenous?

	Mike Lockwood


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