Submicrometer periodicity gratings as artificial anisotropic dielectrics

Flanders, D. C.

doi:10.1063/1.93979

Cited by 195 publications

(102 citation statements)

References 6 publications

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“…(1) and (2), it is seen that the etched layer has an index of refraction that is different for differing polarizations. This birefringence can be quite large and has been measured experimentally (for a single layer of patterned SiOl) to be as much as An = nL-9 = 0.06 '.…”

Section: Anew Technologymentioning

confidence: 97%

<title>Two-dimensional array of optical interference filters produced by lithographic alterations of the index of refraction</title>

Kaushik

Stallard

1995

Application and Theory of Periodic Structures

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We describe a new concept for producing, on a single substrate, a two-dimensional array of optical interference filters where the pass-band of each element can be independently specified. The interference filter is formed by optically contacting two dielectric mirrors so that the top quarter-wave films of the two mirrors form a Fabry-Perot cavity having a half-wave thickness. In the new device, we propose to etch an array of sub-wavelength patterns into the top surface of one of the mirrors before forming the cavity. The patterns must have a pitch shorter than the operational wavelength in order to eliminate diffraction. By changing the index of refraction of the half-wave layer, or the optical thickness of the cavity, the patterning is used to shift the pass-band and form an array of interference filters. One approach to producing the array is to change the fill factor of the pattern. Once the filter array is produced it may be mated to a two-dimensional detector array to form a miniature spectrophotometer.KEYWORDS: sub-wavelength structures, interference filter, spectrophotometer, CURRENT TECHNOLOGY FOR FILTER ARRAYSOptical interference filters appear in a number of forms. The class of filters with the highest transmission and narrowest linewidths are Fabry-Perot filters. These filters are formed by sandwiching a half-wave (or some multiple thereof) spacer layer between two mirrors. The lowest absorptive losses are found in mirrors made from multilayer dielectric stacks that are usually quarter-wave in thickness. The pass-band of these filters (i.e. the center wavelength, b)is determined by the optical thickness of the spacer layer. The bandwidth is determined by both the optical thickness of the spacer layer and the reflectivities of the two mirrors. The most common Fabry-Perot filters commercially available have pass-bands that are spatially uniform with variations as small as 0.1%. Filters with spatially varying pass-bands are also commercially available and are manufactured by proportionally varying the thickness of all the layers uniformly across the surface of the filters. These filters, called wedge filters, are either circular (circular variable filter -CVF) or linear (linear variable filter -LVF). In the former, the thicknesses of the multilayer films vary linearly with the angular position on a circular substrate; in the latter, they vary linearly with position across a rectangular substrate.Although wedge filters are widely used, they have several limitations. First, it is not possible to have both large dispersion (>> 10 d m m ) and retain other desirable characteristics. The dispersion is proportional to the wedge angle; however, a large wedge angle results in poor transmission characteristics (due to n o n -n o d reflections fiom the angled mirror facet), and an increase in spectral bandwidth (due to wavefront inhomogenity across the angled facets). Owing to these limitations, wedge filters are large (e.g. typical LVFs in the 300 nm -700 nm spectral range are 60 mm in length) and have dis...

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Section: Anew Technologymentioning

confidence: 97%

<title>Two-dimensional array of optical interference filters produced by lithographic alterations of the index of refraction</title>

Kaushik

Stallard

1995

Application and Theory of Periodic Structures

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“…Analytical expressions for the tensor elements can be derived analytically using effective medium theory [11,12,17,18]. The geometry and definitions for this analysis are summarized in Figure 1.…”

Section: Derivation Of Effective Medium Parametersmentioning

confidence: 99%

Optimization and Characterization of Negative Uniaxial Metamaterials

Ávila

Valle

Bustamante

et al. 2017

PIER C

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Abstract-Digital manufacturing, or 3D printing, is a rapidly emerging technology which enables novel designs that incorporate complex geometries and even multiple materials. In electromagnetics and circuits, 3D printing allows the dielectrics to take on new and profound functionality. This paper introduces negative uniaxial metamaterials (NUMs) which are birefringent structures that can be used to manipulate electromagnetic fields at a very small scale. The NUMs presented here are composed of alternating layers of two different dielectric materials. The physics of the NUMs are explained and simple analytical equations for the effective dielectric tensor are derived. Using these equations, the NUMs are optimized for strength of anisotropy and for space stretching derived from transformation optics. The analytical equations are validated through rigorous simulations and by laboratory measurements. Three NUMs where manufactured using 3D printing where each exhibited anisotropy in a different orientation for measurement purposes. All of the data from the analytical equations, simulations, and experiments are in excellent agreement confirming that the physics of the NUMs is well understood and that NUMs can be designed quickly and easily using just the analytical equations.

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“…The output signal i,, of the mth photodetector Dm is still given by Eq. (1), where the mth projection vector a, is now given by (5) In general, det(A) =# 0 and the instrument matrix is nonsingular. Singularities occur when any of the multiplied factors in Eq.…”

Section: Photopolarimeter Based On Planar Grating Diffractionmentioning

confidence: 99%

Photopolarimeter based on planar grating diffraction

Azzam

Giardina

1993

J. Opt. Soc. Am. A

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A division-of-amplitude photopolarimeter (DOAP) is described that employs a diffraction grating in the conventional spectrometer orientation with the grating grooves normal to the plane of incidence. Four coplanar diffracted orders are used for polarimetric analysis to determine all four Stokes parameters of incident light simultaneously and virtually instantaneously (with the speed being determined solely by the photodetectors and their associated electronics); a fifth order is used for alignment by autocollimation or by use of a positionsensing quadrant detector. To sensitize the instrument for the +45° and -45° azimuths of incident linearly polarized light and for the handedness of incident circular polarization (i.e., for the third and fourth Stokes parameters), we insert two linear polarizers in two diffracted orders with their transmission axes inclined at appropriate angles with respect to the plane of incidence. The calibration and testing of an instrument of this type that uses an Al-coated 600-groove/mm holographic grating at 632.8-nm wavelength are reported as an example.

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Submicrometer periodicity gratings as artificial anisotropic dielectrics

Cited by 195 publications

References 6 publications

<title>Two-dimensional array of optical interference filters produced by lithographic alterations of the index of refraction</title>

<title>Two-dimensional array of optical interference filters produced by lithographic alterations of the index of refraction</title>

Optimization and Characterization of Negative Uniaxial Metamaterials

Photopolarimeter based on planar grating diffraction

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