Impedance matched to vacuum, invisible edge, diffraction suppressed mirror

Patent metadata

Field	Value
Publication number	US-9012008-B1
Application number	US-201313771815-A
Country	US
Kind code	B1
Filing date	Feb 20, 2013
Priority date	Feb 20, 2013
Publication date	Apr 21, 2015
Grant date	Apr 21, 2015

Abstract

Diffraction suppressed mirrors having an invisible edge are disclosed for incident light at both targeted wavelengths and broadband incident light. The mirrors have a first having at least one discontiguous portion having a plurality of nanostructured apertures. The discontiguous mirror portion impedance matches a relatively high impedance portion of the mirror to a relatively low impedance portion of the mirror, thereby reducing the diffraction edge effect otherwise present in a conventional mirror.

First claim

What is claimed is:

1. An impedance matched to a vacuum, invisible edge diffraction suppressed mirror, comprising:
a first layer having a top surface, a bottom surface, and a thickness;
a first layer contiguous portion having a periphery; and
at least one first layer discontiguous portion disposed about and abutting the contiguous portion periphery, and
wherein the first layer discontiguous portion comprises a plurality of nanostructures, the plurality of nanostructures defining a plurality of apertures extending from the first layer top surface, through the first layer thickness, and to the first layer bottom surface;
the mirror further comprising a central portion having a clear aperture, a first zone proximate the central portion and having a first areal density of nanostructures, a second zone proximate the first zone and having a second areal density of nanostructures, and a third zone having a third areal density of nanostructures where the clear aperture defines a mirror region having high impedance and the region of non-mirror space beyond the mirror zone defines a non-mirror region having low impedance; the mirror first zone, second zone, and third zone comprising nanostructures formed from substantially circular holes extending from the top of the mirror surface to the bottom of the glass substrate, each mirror zone comprising similarly sized nanostructures defined on a zone-specific pitch and zone-specific areal coverage density.

2. The mirror of claim 1 , wherein the contiguous surface portion has a first impedance and the discontiguous surface portion has a second impedance.

3. The mirror of claim 2 , wherein the first impedance is greater than the second impedance.

4. The mirror of claim 1 , wherein the plurality of nanostructures further comprise a critical dimension, and wherein the nanostructure critical dimension determines a range of diffraction suppressed incident light wavelengths.

5. The mirror of claim 1 , further comprising:
a second layer having a top surface, a bottom surface, and a thickness;
a second layer contiguous surface portion having a periphery; and
at least one second layer discontiguous portion disposed about and abutting the contiguous portion periphery,
wherein the second layer top surface is disposed over at least a portion of the first layer bottom surface, and
wherein the second layer discontiguous portion comprises a plurality of nanostructures, the plurality of second layer nanostructures being substantially aligned to the plurality of first layer nanostructures, the plurality of second layer nanostructures defining a plurality of apertures extending from the second layer top surface, through the second layer thickness, and extending to the second layer bottom surface.

6. The mirror of claim 5 , wherein the first layer has a thickness of about 5 microns and the second layer has a thickness of about 100 nanometers.

7. The mirror of claim 5 , wherein the first layer comprises silicon and the second layer comprises aluminum.

8. The mirror of claim 5 , wherein the plurality of nanostructures comprise vias having a critical dimension of about 500 nanometers.

9. An impedance matched to a vacuum, invisible edge diffraction suppressed mirror, comprising:
a substrate having a top surface, a bottom surface, and a thickness;
a centrally disposed first substrate portion having a periphery and defining a clear aperture; and
a second substrate portion having a periphery, the second substrate portion being disposed about the periphery of the first substrate portion,
wherein the second substrate portion comprises a plurality of nanostructures arranged on at least one pitch, the plurality of nanostructures defining a plurality of apertures extending from the substrate top surface, through the substrate thickness, to the substrate bottom surface,
the mirror further comprising a central portion having a clear aperture, a first zone proximate the central portion and having a first areal density of nanostructures, a second zone proximate the first zone and having a second areal density of nanostructures, and a third zone having a third areal density of nanostructures where the clear aperture defines a mirror region having high impedance and the region of non-mirror space beyond the mirror zone defines a non-mirror region having low impedance; the mirror first zone, second zone, and third zone comprising nanostructures formed from substantially circular holes extending from the top of the mirror surface to the bottom of the glass substrate, each mirror zone comprising similarly sized nanostructures defined on a zone-specific pitch and zone-specific areal coverage density.

10. The mirror of claim 9 , wherein the plurality of nanostructures comprises at least three nanostructures arranged at different radial distances from a center of the mirror, a first nanostructure arranged at a first distance from the center of the mirror, a second nanostructure arranged at a second distance from the center of the mirror, and a third nanostructure arranged at a third distance from the center of the mirror;
wherein second distance is greater than the first distance and the third distance is greater than the second distance;
wherein different radial distances between radially adjacent nanostructures radially reduce an impedance of the mirror.

11. The mirror of claim 9 , wherein the first substrate portion is substantially contiguous.

12. The mirror of claim 9 , wherein second substrate portion nanostructures are arranged on about a 1.8 micron pitch.

13. The mirror of claim 9 , wherein the second substrate portion nanostructures comprise about a 16% areal density of a surface area of the second substrate portion.

14. The mirror of claim 9 , further comprising:
a third substrate portion having a periphery, the third substrate portion being disposed about the periphery of the second substrate portion,
wherein the third substrate portion comprises a plurality of nanostructures arranged on at least one second pitch, the plurality of nanostructures defining a plurality of apertures extending from the substrate top surface, through the substrate thickness, to the substrate bottom surface, and
wherein the at least one second pitch of the nanostructures in the third substrate portion is smaller than the at least one first pitch of the nanostructures in the second substrate portion.

15. The mirror of claim 14 , wherein the third substrate portion nanostructures are arranged on about a 1.5 micron pitch.

16. The mirror of claim 14 , wherein the third substrate portion nanostructures comprise about a 20% areal density of a surface area of the third substrate portion.

17. The mirror of claim 14 , further comprising:
a forth substrate portion having a periphery, the fourth substrate portion being disposed about the periphery of the third substrate portion,
wherein the fourth substrate portion comprises a plurality of nanostructures arranged on at least one third pitch, the plurality of nanostructures defining a plurality of apertures extending from the substrate top surface, through the substrate thickness, to the substrate bottom surface, and
wherein the at least one third pitch of the nanostructures in the fourth substrate portion is smaller than the at least second pitch of the nanostructures in the third substrate portion.

18. The mirror of claim 17 , wherein the fourth substrate portion nanostructures are arranged on about a 600 nanometer pitch.

19. The mirror of claim 17 , wherein the fourth substrate portion nanostru

Assignees

• Us Of America As Represented By The Administrator Of The Nat Aeronautics And Space Administration
• Nasa

Inventors

• Hagopian John G
• Roman Patrick A
• Shiri Sharham
• Wollack Edward J

Classifications

• G02B5/08

  Mirrors {(vehicle mirrors involving special optical features B60R1/08)} · CPC title

• G02B5/0816 Primary

  Multilayer mirrors, i.e. having two or more reflecting layers (G02B5/0883, G02B5/0891 take precedence) · CPC title

• G02B27/58

  Optics for apodization or superresolution; Optical synthetic aperture systems · CPC title

• Y10T428/24273

  including aperture · CPC title

• G02B2207/101

  Nanooptics · CPC title