Gindex

II-VI REPORT

March 31, 2000

This is the trip report of Heidi Yarborough and Allen Davis to II–VI Inc. on 03/31/2000.

We arrived at 8:45 am and first met Mr. John Green. We told him what we wanted to accomplish with the inspection of the two mirrors, then Mr. Green gave us a tour of the plant. After that, Mr. Green took us to inspection and diamond turning to see the mirrors that II–VI Inc. was doing for AURA Inc.

It was here that Heidi and I saw how II-VI inspect and measure the mirrors and print out the results, which are shown at the end of this report.

We asked two questions:

1.Can II-VI determine if the mirrors will retain their figures when they are removed from the fixture?

A.The answer is that first they take a picture of the mirror with the bolts torqued on the fixture with the Zygo GPI –XP. Then they un-torque the bolts,take another picture with the ZYGO GPI-XP, and see if the two pictures show any stress or other problems.

2.How does II-VI maintain the perpendicularity and parallelism of their test fixture?

A.The answer is they do it with a machine called the Nanoform 600. First they diamond turn the mirror on this machine, then they measure the mirror to the specification they are working from. The second diamond turning fixes any discrepancies from the original specifications.

After Heidi saw the results of the inspection, she said that both mirrors were acceptable.

While Heidi Yarborough was busy verifying the two mirrors, Alan Hedges and I had a talk about diamond turning midlevel frequency. Because I did not understand the question that Alan Hedges was asking I made a call to NOAO and talked to Neil and Dick Joyce about this and they said it was not a problem.

Attached to this trip report are the II-VI Inspection Reports and the pictures of the two mirrors that were taken with the Zygo.

Mr. John Green told us that the Offner Primary, Off-Axis Collimator, and the Secondary Offner mirrors were to be gold coated all at the same time and this should happen in about three or four weeks.

We left II-VI about 12:30pm.

Sincerely,

Allen Davis

Vendor Liaison