Mr. Ronald R. Willey Profile

Ronald R. Willey

Consultant

SPIE Involvement:

Author | Instructor

Area of Expertise:

Optical Thin Film Coating Training , Optical Thin Film Coating Process Help , Optical Thin Film Coating Consulting , Legal Expert Witness , Optical Thin Film Coating books , Optical System Design

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Publications (18)

Proceedings Article | 12 September 2021 Presentation + Paper

Non-polarizing narrow bandpass and other filters at angles

Ronald Willey

Proceedings Volume 11872, 1187208 (2021) https://doi.org/10.1117/12.2596894

KEYWORDS: Reflectivity, Polarization, Refraction, Optical filters, Beam splitters, Bandpass filters, Thin films, Reflection, Prisms, Linear filtering

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One of the more challenging aspects of optical thin film design has been to design the s- and p-polarizations of a filter to have the same reflectance as each other at a given angle of incidence. There have been various contributions in the literature for over half of a century to the understanding of this behavior. Some of these works are reviewed and their results are illustrated in newer graphic formats with examples. Baumeister, in 1961, reported in Optica Acta on “The Transmission and Degree of Polarization of Quarter-wave Stacks at Non-normal Incidence.” In 1970, Costich described a method of transforming massive media to nonpolarizing effective massive media. He applied two design techniques to the problem of making polarization independent metal-dielectric-metal interference filters and polarization independent beam splitters. The polarization dependence of interference coatings may be reduced by combining two approaches. The first is the use of a polarization insensitive layer combination, and the second is to transform the massive media to effective massive media having little polarization splitting of their effective indices. In 1976, Thelen reported on nonpolarizing interference films inside a glass cube. He described another method using only quarter-wave layers including the equations to accomplish this and he refers to the work of Baumeister reported from 1961. He points out some limitations to the Costich approach. Henderson showed the benefits of using three materials instead of only two in a 1978 paper. Two materials could be made non-polarizing for one wavelength and angle, but three materials would provide non-polarizing performance over a broader wavelength range. At normal incidence, a layer-pair of quarter waves of high and low indices is the basic building block to stack one layer-pair upon another to create a high reflection at a given wavelength band centered at the design wavelength for which the layers are quarter-waves. When plotted on a Fresnel Reflectance Amplitude diagram, each quarter-wave forms a semicircle at the design wavelength, and the layer pair then covers 360°. In the case of non-polarizing designs, the building blocks composed of three materials are formed from four quarter-waves or 720° of phase change. These have the property at the design wavelength and angle to advance the reflectance equally for both the s- and p-polarization. There is an apparent similarity here between the effect of this medium-index layer and the typical halfwave thickness high index layer as an achromatizing layer for a three material broadband four quarter-wave antireflection coating design. There is also a similarity on a reflectance amplitude diagram to the mathematical shape of a Limacon for both the s- and p-polarization. The s- polarization has an obvious internal Limacon loop and the p-loop expands to appear more as a spiral in some cases. The Herpin/Epstein concept might lead one to consider accomplishing the function of the three-material designs with only two materials. The possibilities and limitations of only two-material designs are examined.

Proceedings Article | 5 June 2018 Paper

Stable, durable, low-absorbing, low-scattering MgF2 films without heat or added fluorine

Ronald Willey, R. Shakoury

Proceedings Volume 10691, 106910C (2018) https://doi.org/10.1117/12.2309812

KEYWORDS: Fluorine, Ions, Absorption, Scattering, Chemical species, Magnesium fluoride, Oxygen, Ultraviolet radiation, Magnesium, Argon

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Proceedings Article | 4 October 2011 Paper

Effect of substrate index of refraction on the design of antireflection coatings

Ronald Willey

Proceedings Volume 8168, 81680C (2011) https://doi.org/10.1117/12.898517

KEYWORDS: Reflectivity, Refraction, Coating, Antireflective coatings, Autoregressive models, Fourier transforms, Optical coatings, Thin films, Current controlled current source, Absorption

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Proceedings Article | 25 September 2008 Paper

Design and monitoring of narrow bandpass filters composed of non-quarter-wave thicknesses

Ronald Willey

Proceedings Volume 7101, 710119 (2008) https://doi.org/10.1117/12.792361

KEYWORDS: Transmittance, Bandpass filters, Mirrors, Optical filters, Optical components, Electronic filtering, Reflectors, Antireflective coatings, Computer programming, Optical coating design

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SPIE Press Book | 27 January 2006

Field Guide to Optical Thin Films

Ronald Willey

KEYWORDS: Coating, Reflectivity, Reflection, Thin films, Refraction, Antireflective coatings, Thin film coatings, Chromium, Reflectors

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Proceedings Article | 5 October 2005 Paper

Study of potential quantization effects in designs for 12.4 nm mirrors

Ronald Willey

Proceedings Volume 5963, 59632K (2005) https://doi.org/10.1117/12.658997

KEYWORDS: Molybdenum, Silicon, Atomic layer deposition, Reflectivity, Mirrors, Focus stacking software, Quantization, Epitaxy, Crystals, Glasses

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Proceedings Article | 25 February 2004 Paper

Monitoring the last two (AR) layers in narrow-bandpass filters

Ronald Willey

Proceedings Volume 5250, (2004) https://doi.org/10.1117/12.510715

KEYWORDS: Surface plasmons, Dense wavelength division multiplexing, Transmittance, Bandpass filters, Reflectivity, Optical filters, Electronic filtering, Autoregressive models, Crystals, Antireflective coatings

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Proceedings Article | 25 February 2004 Paper

Refined criteria for estimating limits of broadband AR coatings

Ronald Willey

Proceedings Volume 5250, (2004) https://doi.org/10.1117/12.515611

KEYWORDS: Autoregressive models, Antireflective coatings, Reflectivity, Data modeling, Quantization, Optical coatings, Reflection, Refraction, Statistical analysis, Optical coating design

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Proceedings Article | 7 September 1999 Paper

Constrained optimization of band-edge filter matching layers

Ronald Willey

Proceedings Volume 3738, (1999) https://doi.org/10.1117/12.360127

KEYWORDS: Reflectivity, Transmittance, Optical filters, Antireflective coatings, Reflection, Information operations, Interfaces, Optical coating design, Refraction, Diffractive optical elements

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Proceedings Article | 19 August 1996 Paper

Application of oxygen IAD using a new high-power gridless plasma source

Ronald Willey

Proceedings Volume 2776, (1996) https://doi.org/10.1117/12.246807

KEYWORDS: Ions, Amplifiers, Oxygen, Argon, Plasma, Electrons, Coating, Ion beams, Power supplies, Diffractive optical elements

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Proceedings Article | 4 November 1994 Paper

Overcoming low index limitations in antireflection coatings with additional thickness

Ronald Willey

Proceedings Volume 2253, (1994) https://doi.org/10.1117/12.192154

KEYWORDS: Reflectivity, Antireflective coatings, Coating, Interfaces, Reflection, Autoregressive models, Refraction, Thin film coatings, Germanium, Magnesium fluoride

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Proceedings Article | 7 September 1994 Paper

Some comparisons in the application of End-Hall and Cold Cathode ion sources in the conversion of SiO to SiO2

Ronald Willey

Proceedings Volume 2262, (1994) https://doi.org/10.1117/12.185787

KEYWORDS: Ions, Oxygen, Amplifiers, Control systems, Silica, Coating, Silicon, Argon, Humidity, Molybdenum

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Proceedings Article | 2 November 1993 Paper

Basic nature and properties of inhomogeneous antireflection coatings

Ronald Willey

Proceedings Volume 2046, (1993) https://doi.org/10.1117/12.163560

KEYWORDS: Antireflective coatings, Reflectivity, Coating, Refraction, Light emitting diodes, Optical design, Interfaces, Crown glass

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Proceedings Article | 4 March 1993 Paper

New viewpoint on the synthesis of thin films using Fourier transforms

Ronald Willey

Proceedings Volume 1782, (1993) https://doi.org/10.1117/12.141052

KEYWORDS: Reflectivity, Reflection, Thin films, Fourier transforms, Interfaces, Distortion, Antireflective coatings, Germanium, Optical coating design, Reflectors

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SPIE Journal Paper | 1 March 1993

Corrosion-resistant front surface aluminum mirror coatings

Karl Guenther, Iain Penny, Ronald Willey

OE, Vol. 32, Issue 03, (March 1993) https://doi.org/10.1117/12.10.1117/12.60845

KEYWORDS: Aluminum, Mirrors, Dielectrics, Ions, Silicon, Thin film coatings, Electron beams, Thin films, Plating, Plasma

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Proceedings Article | 28 December 1992 Paper

Maximizing production yield and performance in optical instruments through effective design and tolerancing

Ronald Willey, Mark Durham

Proceedings Volume 10265, 1026505 (1992) https://doi.org/10.1117/12.61102

KEYWORDS: Tolerancing, Optical components, Optical instrument design, Product engineering, Prototyping

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Proceedings Article | 1 January 1991 Paper

Ways that designers and fabricators can help each other

Ronald Willey, Mark Durham

Proceedings Volume 1354, (1991) https://doi.org/10.1117/12.47957

KEYWORDS: Glasses, Prisms, Lens design, Tolerancing, Cements, Reflection, Interfaces, Monochromatic aberrations, Coating, Manufacturing

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Proceedings Article | 1 August 1990 Paper

Design of wideband antireflection coating with the Fourier transform method

Ronald Willey, Pierre Verly, Jerzy Dobrowolski

Proceedings Volume 1270, (1990) https://doi.org/10.1117/12.20362

KEYWORDS: Antireflective coatings, Fourier transforms, Refractive index, Multilayers, Reflectivity, Autoregressive models, Thin films, Optical coating design, Germanium, Interfaces

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Showing 5 of 18 publications

Course Instructor

SC209: Practical Design and Production of Optical Thin Films

Advanced optical thin films are being used in optical systems, communications, and light control applications. The industry is advancing rapidly to meet demands for performance and production capacity. This short course describes optical thin films, components and processes. New viewpoints, equipment, and processes are available to support advanced capability and efficiency.

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