Re: super polish

From: Parallax (dbohara_at_mindspring.com)
Date: 06/25/04 

Date: 24 Jun 2004 20:07:57 -0700

ezp1@comcast.net (Taff) wrote in message news:<d916bee5.0406240457.53bdb35@posting.google.com>...
> > >>Hi All,
> > >>I was wondering if there is a definition for the surface roughness of
> > >>an optic when it comes to the term "super polish".
> > >>It seems as though there are companies out there that quote all sorts
> > >>of numbers but seem to be measuring in all styles of measurement.
> > >>
> > >>Thanks
> > >>
> > >>Taff
> > >
> > >
> > > We achieve surface roughness of less than 10 angstroms with
> > > electroless nickel surfaces, replicated nickel (electrolytic) surfaces
> > > and similar surfaces coated with various materials. Measurements are
> > > made with AFM scanning over a length of about 10 microns. Electroless
> > > nickel can be polished to this level using a fine diamond slurry.
> > >
> > > David OHara
> > > Parallax Research, Inc.
> > > www.parallax-x-ray.com
> >
>
>
>
> Would an RMS value of 0.10 angstroms on a fused silica surface be
> really something then and what applications would that be used for
>
> Taff.

I would say that is very good. However, the distance over which that
measurement is made should be specified, ie. the spatial period of the
roughness. Ultra-smooth optical surfaces can serve as substrates for
x-ray optics (my obsession) and for ultra-low scatter optics.