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A new antireflective coating?

Started by phil426, 03/10/2007 01:59PM
Posted 03/10/2007 01:59PM Opening Post
I'm reading the March 3 Science News about a new antireflective coating that has a refractive index of 1.05. Does anyone know what the current antireflective coatings value is and is this something we can expect in telescope lense coatings in the future?

Kennewick, WA.
AP 152(old blue)on CI700 w/80mm f/11 guider, C-8 on forks w/80mm f/5 guider, 20x80 binos, ST5C, 201XT, Ricoh 35mm, 20Da.
Posted 03/10/2007 02:06PM #1
It's not new. It's an old concept, and unfortunately it has no real application to amateur optics. It's more for things like photocells.

Modern multi-layer coatings can get surface reflectivity down below 0.2%. There is not one particular value of index for a multi-layer coating. It is made of alternating high, medium, and low index materials. The layers are matched to the glass index.

Posted 03/10/2007 02:34PM | Edited 03/10/2007 02:36PM #2
Magnesium Fluoride, the stuff often used in single-layer coatings
has a refractive index of 1.39.

In this new technology they are layering silica nano-rods on
the surface. It looks sort of like a deep pile carpet
on the surface, but only a 1/4 wave thick. Since there are
lots of airspaces, the effective refractive index will be
between that of silica and air. I've not seen any discussion
of using it on optical-grade lenses.