Lighting device including a collimating metalens

Patent metadata

Field	Value
Publication number	US-10408419-B2
Application number	US-201816172274-A
Country	US
Kind code	B2
Filing date	Oct 26, 2018
Priority date	Sep 23, 2015
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

Lighting devices including metalenses are disclosed. In some embodiments, the metalenses are in the form of a hybrid multi-region collimating metalens that includes a first region and a second region, wherein the hybrid multi-region collimating metalens is configured to collimate (e.g., visible) light incident thereon. In some instances the first region includes an array of first unit cells that contain sub-wavelength spaced nanostructures, such that the first region functions as a sub-wavelength high contrast grating (SWHCG), whereas the second region includes an array of second unit cell, wherein the array of second unit cells includes a near periodic annular arrangement of nanostructures such that the second region approximates the functionality of a locally periodic radial diffraction grating.

First claim

What is claimed is:

1. A lighting device ( 495 , 595 ), comprising:
a first light source ( 409 , 502 ); and
a collimating metalens ( 401 , 501 ) proximate said first light source ( 409 , 502 ), said collimating metalens ( 401 , 501 ) comprising:
a substrate ( 303 ) having a first side ( 309 ) and a second side ( 311 ); and
a metasurface ( 305 ) formed on said first side ( 309 );

wherein:
said first light source ( 409 , 502 ) is configured to emit light rays ( 415 , 503 ) in a first wavelength or wavelength range, at least a portion of said light rays ( 415 , 503 ) being incident on said collimating metalens ( 401 );
said collimating metalens ( 401 ) is configured to collimate said light rays ( 415 , 503 ), thereby producing collimated light rays ( 415 , 503 ) in a region down field (DFR) of said collimating metalens ( 401 , 501 ), relative to said first light source ( 409 , 502 ); and
the metasurface ( 305 ) comprises TiO 2 .

2. The lighting device ( 495 , 595 ) of claim 1 , wherein the TiO 2 is amorphous.

3. The lighting device ( 495 , 595 ) of claim 1 , wherein the TiO 2 is in the form of nanostructures having dimensions no greater than 1 μm.

4. The lighting device ( 495 , 595 ) of claim 1 , wherein the nanostructures are separated from nearest neighbor nanostructures by a period from about 50 to about 1,000 nm.

5. The lighting device ( 495 , 595 ) of claim 1 , wherein the TiO 2 is in the form of nanostructures having a cylindrical pillar shape.

6. The lighting device ( 495 , 595 ) of claim 5 , wherein the cylindrical pillars have a height from about 50 to about 2,000 nm.

7. The lighting device ( 495 , 595 ) of claim 6 , wherein the cylindrical pillars have a radius from about 25 to about 500 nm.

8. A method for collimating light, using a lighting device that comprises:
a first light source ( 409 , 502 ); and
a collimating metalens ( 401 , 501 ) proximate said first light source ( 409 , 502 ), said collimating metalens ( 401 , 501 ) comprising:
a substrate ( 303 ) having a first side ( 309 ) and a second side ( 311 ); and
a metasurface ( 305 ) comprising TiO 2 formed on said first side ( 309 ),

the method comprising:
emitting light rays ( 415 , 503 ) from the first light source ( 409 , 502 ) in a first wavelength or wavelength range, at least a portion of said light rays ( 415 , 503 ) being incident on said collimating metalens ( 401 ); and
collimating the light rays ( 415 , 503 ) with the collimating metalens ( 401 ), thereby producing collimated light rays ( 415 , 503 ) in a region down field (DFR) of said collimating metalens ( 401 , 501 ), relative to said first light source ( 409 , 502 ).

Assignees

• Harvard College

Inventors

• Aieta Francesco
• Capasso Federico

Classifications

• F21V5/046

  the lens having a rotationally symmetrical shape about an axis for transmitting light in a direction mainly perpendicular to this axis, e.g. ring or annular lens with light source disposed inside the ring · CPC title

• F21V5/045 Primary

  the lens having discontinuous faces, e.g. Fresnel lenses · CPC title

• F21V5/002

  using microoptical elements for redirecting or diffusing light · CPC title

• F21K9/64

  using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer · CPC title

• G02B1/002

  made of materials engineered to provide properties not available in nature, e.g. metamaterials · CPC title