Holey optical device

• US 10,042,091 B2
• Filed: 09/26/2013
• Issued: 08/07/2018
• Est. Priority Date: 09/29/2012
• Status: Active Grant

• Current Assignee: Purdue Research Foundation (Purdue University)
• Original Assignee: Purdue Research Foundation (Purdue University)
• Inventors: Kildishev, Alexander, Ishii, Satoshi, Shalaev, Vladimir
• Primary Examiner(s): Alexander, William R
• Assistant Examiner(s): PARBADIA, BALRAM T
• Application Number:
  US14/431,544
• Publication Number:
  US 20150247960A1
• Time in Patent Office: 1,776 Days
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 1/002 made of materials engineered to provide properties not available in nature, e.g. metamaterials
• CPC Class Codes: G02B 1/005 made of photonic crystals or photonic band gap materials photonic band-gap structures or photonic lattices in integrated optics G02B6/1225; photonic band-gap structures or photonic lattices in optical fibres G02B6/02295
• CPC Class Codes: G02B 2207/101 Nanooptics
• CPC Class Codes: G02B 3/0087 with index gradient
• CPC Class Codes: G02B 3/08 with discontinuous faces, e.g. Fresnel lens diffractive Fresnel lenses G02B5/1876
• CPC Class Codes: G02B 5/008 Surface plasmon devices diffractive gratings with a pitch less than or comparable to the wavelength G02B5/1809; surface plasmons in integrated optics G02B6/1226; optical analysis of materials by means of surface plasmons G01N21/553
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: G02B 6/1226 involving surface plasmon interaction
• CPC Class Codes: G02B 6/262 Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements
• CPC Class Codes: G02F 1/2255 controlled by a high-frequency electromagnetic component in an electric waveguide structure
• CPC Class Codes: G02F 1/365 in an optical waveguide structure G02F1/377, G02F1/395 take precedence
• CPC Class Codes: G02F 1/397 Amplification of light by wave mixing involving an interference pattern, e.g. using photorefractive material
• CPC Class Codes: G02F 2203/06 Polarisation independent
• CPC Class Codes: G02F 2203/13 involving THZ radiation
• CPC Class Codes: G02F 2203/50 Phase-only modulation
• CPC Class Codes: Y10S 977/888 Shaping or removal of materials, e.g. etching

Abstract

A planar optical device, comprised of sets of nanometer-scale holes milled into a thin metal or ceramic film of subwavelength thickness serves to form arbitrary waveform of light. The holes form a pattern, preferrably rings, of various sizes in order to achieve a given phase front of light due to photonic effect. When designed as a lens, the device focuses incident light into a tight focal spot. In symmetric design, the focusing property of the device does not depend on the incident polarization angle. The lens can be manufactured based on high-throughput fabrication methods and easily integrated with a chip or placed at the end of an optical fiber.

Claims

1. A planar polarization-independent optical device for arbitrary waveform formation, comprising:

a plurality of subwavelength-scale holes with varying radii milled vertically into a film, wherein said holes form a pattern, wherein a radius of each hole determines an effective refractive index for said hole, said effective refractive index modifying a phase and an intensity of an incoming electromagnetic radiation as the radiation propagates through said hole, and wherein a desired phase front of total outputted electromagnetic radiation emitted out of all holes is created, thus achieving phase control in said film, wherein the device is operating equally for each linearly polarized radiation simultaneously, wherein the each linearly polarized radiation is normally incident on the device.

2. The device of claim 1, wherein a focal distance of the optical device, which is operating as a lens, is controlled by adjustment of a wavelength of the incoming electromagnetic radiation.

3. The device of claim 2, wherein a focal distance of the optical device is in the range from one to twenty micrometer.

4. The device of claim 1, further comprising a filler applied to the device after the holes are milled, the filler filling the holes.

5. The device of claim 4, wherein the filler is a non-linear Kerr medium.

6. The device of claim 5, wherein the Kerr medium changes an intensity of incident electromagnetic radiation and controls the device operation in real time.

7. The device of claim 6, further comprising a control unit, the control unit applying a signal to the device thus changing an operating function of the device in real time with THz frequency.

8. The device of claim 4, wherein the filler is a gain medium serving for amplification of the radiation intensity and compensation for plasmonic losses.

9. The device of claim 1, wherein said film is a pure metal film comprised of gold, aluminum, silver, or copper.

10. The device of claim 1, wherein said film is a ceramic film made of silicon carbide.

11. The device of claim 1, wherein said film is a non-stoichiometric ceramic film made of titanium nitride, or zirconium nitride.

12. The device of claim 1, wherein the phase change increases as the hole radius becomes larger.

13. The device of claim 1, wherein said film comprises gold, silver, or copper.

14. A method for arbitrary waveform formation, comprising:

milling a pattern of a plurality of subwavelength-scale holes into a film, wherein said pattern comprises holes of varying width corresponding to a desired effective refractive index within each hole, wherein said effective refractive index of each individual hole modifies a phase and an intensity magnitude of the radiation propagating through said individual hole, and outputting an output radiation, wherein said output radiation propagates through each individual hole and experiences various refractive modifications, thus outputting a desired phase front of radiation from all holes in said film, wherein an entirety of the film comprises a pure metal, wherein a device containing the film is operating equally for each linearly polarized radiation simultaneously, wherein the each linearly polarized radiation is normally incident on the device.

15. The method of claim 14, wherein the radiation is a radiation in an optical range.

16. The method of claim 14, wherein prior to milling,

depositing the film on a fiber core covered with an adhesive layer.

17. The method of claim 14, further comprising:

applying a filler to the holes after the holes are milled, the filler filling the holes, the filler is a non-linear Kerr medium.

18. The method of claim 17, wherein the Kerr medium changes an intensity of incident

electromagnetic radiation and controls the device operation in real time.

19. The method of claim 14, wherein the pure metal film comprises gold, aluminum, silver, or copper.