Tag: Coatings

Anti-Reflection Coatings Part III: Oblique Incidence

December 24, 2024

Dealing with Non-normal Incidence In the previous post we developed the TMM for the special case of light incident in a direction perpendicular onto a multilayer coating. And as developed in the post before that, our treatment of the reflection and transmission coefficients required nothing more complicated than some commonsense assumptions about the behavior of … More Anti-Reflection Coatings Part III: Oblique Incidence

Anti-Reflection Coatings Part II: The Transfer Matrix Method

December 14, 2024

The Headache of Multiple Layers In the previous post we calculated the effect of a single dielectric layer placed between air and glass, and showed that with a judicious selection of index and thickness, it would serve as an anti-reflection coating that would pass 100% of the light at a nominal wavelength, and at least … More Anti-Reflection Coatings Part II: The Transfer Matrix Method

Anti-Reflection Coatings, Part I: Single Layer

December 11, 2024

Introduction It is well-known that the transmission of light through optical components such as lenses and prisms can be improved through the application of specialized dielectric coatings. We’ve come to take them for granted, and can easily forget that without them, the views through our instruments would be significantly dimmer. Any curious user of binoculars, … More Anti-Reflection Coatings, Part I: Single Layer

The Physics of Roof Prisms and Phase Coatings, Simplified: Part II

August 18, 2023

Phase shifts and interference The previous post introduced the topic of roof prism performance loss resulting from phase shifts that accompany total internal reflection (TIR). These shifts are endemic to TIR and to any device that employs it, including not only roof but Porro prisms. But in the latter case, the shifts have no deleterious … More The Physics of Roof Prisms and Phase Coatings, Simplified: Part II

The Physics of Roof Prisms and Phase Coatings

July 22, 2023

I’ve written a technical article on the topic of why the roof prisms used in binoculars require specialized coatings in order to improve their performance. I was prompted to pull this together because I couldn’t find a single reference that traced through this interesting problem in a non-trivial way. The article includes a derivation of … More The Physics of Roof Prisms and Phase Coatings