RE: [ATM] Scaling wavefront error

["James Mulherin" <jcmulherin@opticalmechanics.com>]

Steve, Mark, Jim:

I'm a little embarrassed to admit that until recently I didn't realize my
fringe analysis software could automatically scale the test results from the
test wavelength of 633 nm to 550 nm. I figured this out recently after
someone asked a question about scaling results on the Torusmirrors group.
Any way, we've switched to a 532 nm laser and I will be scaling the test
results to 550 nm. The results we post are wavefront error (not surface).

James

James Mulherin
President/Master Optician
Optical Mechanics, Inc.
jcmulherin@opticalmechanics.com
www.ProSpecMirrors.com
Tel: (319) 351-3960
Fax: (319) 351-3943

> -----Original Message-----
> From: Koehler, Steve [mailto:Steve_Koehler@securecomputing.com]
> Sent: Monday, July 12, 2004 9:55 AM
> To: atm@atmlist.net
> Cc: jcmulherin@opticalmechanics.com
> Subject: RE: [ATM] How much cell induced deformation is too much?
> 
> Jim (and Mark),
> 
> > >Anybody
> > >know if they reference HeNe laser (633nM) or something else?
> >
> > Boy, I sure hope they don't!  Another cheat like quoting surface
> > aberrations without saying it, while everybody is assuming wavefront.
> > It's
> > certainly OK to test with lasers, but the final answer should be, if
> given
> > as RMS, PV, or Strehl, referenced to the standard 550 nm visual
> > wavelength.
> 
> OMI (Torus) has been reporting results using 633 nm.  Although they don't
> mention it directly on on-line specs page for each mirror, it is clearly
> stated in information they provide that explains the interferometric
> results:
> 
> "The wavefront quality specification for Optical Mechanics Pro-Spec
> mirrors is 0.0712l RMS at 633nm with a Strehl ratio of 0.8 or higher. The
> P-V
> wavefront error is not used in the specification, however it is reported
> in
> the interferometric test report provided with each mirror and is typically
> less than 0.25l. Each Torus Pro-Spec mirror must meet or exceed these
> specifications before it is certified for shipment to the customer. Every
> mirror is delivered with its interferometric test report and a Certificate
> of
> Optical Quality."
> 
> Personally, I think it would be much better to scale the results to 550
> mn,
> But I don't think OMI has been reporting at 633 nm to inflate the numbers.
> Mulherin recently announced on the Torusmirrorgroup that he will be
> switching
> to reporting results at 550 nm, starting with the next batch of mirrors he
> reports.  (He also mentioned that he will be changing the test photos to
> include to include a null knife-edge image and a null Ronchi image with
> only
> a few lines.)
> 
> I don't think Mulherin is currently listening on this list, so I'm Cc'ing
> him
> on my response, in case he would like to respond directly.
> 
> -- Steve Koehler
>    steve_koehler@securecomputing.com
> 


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