Realization and Comparison of the Antireflection(AR) Coating in Graded and Quintic Index Profile

This work presents fundamental understanding of the correlation between nanoindentation hardness and practical scratch resistance for mechanically tunable anti-reflective (AR) hardcoatings. These coatings exhibit a unique design freedom, allowing quasi-continuous variation in the thickness of a central hardcoat layer in the multilayer design, with minimal impact on anti-reflective optical performance. This allows detailed study of anti-reflection coating durability based on variations in hardness vs. depth profiles, without the durability results being confounded by variations in optics. Finite element modeling is shown to be a useful tool for the design and analysis of hardness vs. depth profiles in these multilayer films. Using samples fabricated by reactive sputtering, nanoindentation hardness depth profiles were correlated with practical scratch resistance using three different scratch and abrasion test methods, simulating real world scratch events. Scratch depths from these experiments are shown to correlate to scratches observed in the field from consumer electronics devices with chemically strengthened glass covers. For high practical scratch resistance, coating designs with hardness >15 GPa maintained over depths of 200–800 nm were found to be particularly excellent, which is a substantially greater depth of high hardness than can be achieved using previously common AR coating designs.

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Inverse estimation of temperature-dependent refractive index profile in conductive-radiative media

Inverse Problems in Science and Engineering ◽

10.1080/17415985.2021.1932872 ◽

2021 ◽

pp. 1-18

Author(s):

H. Shafiee ◽

S. M. Hosseini Sarvari

Keyword(s):

Refractive Index ◽

Refractive Index Profile ◽

Index Profile ◽

Temperature Dependent ◽

Inverse Estimation

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Influence of Rugate Filters on the Spectral Manifestation of Tamm Plasmon Polaritons

Materials ◽

10.3390/ma14051282 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1282

Author(s):

Victor Reshetnyak ◽

Igor Pinkevych ◽

Timothy Bunning ◽

Dean Evans

Keyword(s):

Refractive Index ◽

Band Gap ◽

External Medium ◽

Metal Layer ◽

Refractive Index Profile ◽

Spectral Position ◽

Index Profile ◽

Reflection And Transmission ◽

Rugate Filter ◽

Plasmon Polaritons

This study theoretically investigated light reflection and transmission in a system composed of a thin metal layer (Ag) adjacent to a rugate filter (RF) having a harmonic refractive index profile. Narrow dips in reflectance and peaks in transmittance in the RF band gap were obtained due to the excitation of a Tamm plasmon polariton (TPP) at the Ag–RF interface. It is shown that the spectral position and magnitude of the TPP dips/peaks in the RF band gap depend on the harmonic profile parameters of the RF refractive index, the metal layer thickness, and the external medium refractive index. The obtained dependences for reflectance and transmittance allow selecting parameters of the system which can be optimized for various applications.

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ANALYSIS OF OPTICAL WAVEGUIDES WITH ARBITRARY INDEX PROFILE USING AN IMMERSED INTERFACE METHOD

International Journal of Modern Physics C ◽

10.1142/s0129183111016543 ◽

2011 ◽

Vol 22 (07) ◽

pp. 687-710 ◽

Cited By ~ 4

Author(s):

THEODOROS P. HORIKIS

Keyword(s):

Optical Waveguides ◽

Eigenvalue Problems ◽

Numerical Technique ◽

Interface Problems ◽

Index Profile ◽

Immersed Interface Method ◽

Immersed Interface ◽

Light Confinement ◽

Bragg Fibers ◽

Matrix Eigenvalue Problems

A numerical technique is described that can efficiently compute solutions of interface problems. These are problems with data, such as the coefficients of differential equations, discontinuous or even singular across one or more interfaces. A prime example of these problems are optical waveguides, and as such the scheme is applied to Maxwell's equations as they are formulated to describe light confinement in Bragg fibers. It is based on standard finite differences appropriately modified to take into account all possible discontinuities across the waveguide's interfaces due to the change of the refractive index. Second- and fourth-order schemes are described with additional adaptations to handle matrix eigenvalue problems, demanding geometries and defects.

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