Spectral filter for green and shorter wavelengths
First Claim
1. An optical spectral filter for spectral filtering of light at green and shorter wavelengths, comprisinga substrate or host wafer having an array of substantially uniform parallel hollow pores therethrough, the pores having a characteristic lateral dimension in the plane of the host wafer within the range of from about 0.1 μ
- m to about 20 μ
m, each pore supporting at least one waveguide mode in the transparency wavelength range of said filter, said wafer having first and second surfaces substantially perpendicular to the axis of the pores, and wherein the walls of each pore are coated with at least one layer of substantially transparent material at the transparency wavelength range of said filter and wherein the thickness of each of said layers of transparent material is at least 10 nm.
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Abstract
The UV, deep UV and/or far UV (ultraviolet) filter transmission spectrum of an MPSi spectral filter is optimized by introducing at least one layer of substantially transparent dielectric material on the pore walls. Such a layer will modify strongly the spectral dependences of the leaky waveguide loss coefficients through constructive and/or destructive interference of the leaky waveguide mode inside the layer. Increased blocking of unwanted wavelengths is obtained by applying a metal layer to one or both of the principal surfaces of the filter normal to the pore directions. The resulting filters are stable, do not degrade over time and exposure to UV irradiation, and offer superior transmittance for use as bandpass filters. Such filters are useful for a wide variety of applications including but not limited to spectroscopy and biomedical analysis systems.
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Citations
60 Claims
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1. An optical spectral filter for spectral filtering of light at green and shorter wavelengths, comprising
a substrate or host wafer having an array of substantially uniform parallel hollow pores therethrough, the pores having a characteristic lateral dimension in the plane of the host wafer within the range of from about 0.1 μ - m to about 20 μ
m, each pore supporting at least one waveguide mode in the transparency wavelength range of said filter, said wafer having first and second surfaces substantially perpendicular to the axis of the pores, and wherein the walls of each pore are coated with at least one layer of substantially transparent material at the transparency wavelength range of said filter and wherein the thickness of each of said layers of transparent material is at least 10 nm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59)
- m to about 20 μ
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60. An optical spectral filter for green and shorter offer wavelengths comprising
a substrate having an array of substantially uniform parallel hollow pores therethrough, the pores having a characteristic lateral dimensions in the plane of the substrate, each pore supporting at least one waveguide mode a transparency wavelength range of said filter, said substrate having first and second surfaces substantially perpendicular to the axis of the pores, and wherein the walls of each pore are coated with at least one layer of substantially transparent material at the transparency wavelength range of said spectral filter.
Specification