Optical devices with engineered nonlinear nanocomposite materials

• US 7,020,372 B2
• Filed: 07/16/2004
• Issued: 03/28/2006
• Est. Priority Date: 08/02/2001
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: UltraDots, Inc. (Omnipv Incorporated)
• Inventors: Pfenninger, William Matthew, Lee, Howard Wing Hoon, Chin, Alan Hap
• Primary Examiner(s): Lee, John D.
• Assistant Examiner(s): Stein, James D.
• Application Number:
  US10/893,719
• Publication Number:
  US 20050058416A1
• Time in Patent Office: 620 Days
• Field of Search: 385/5, 385/16, 385/122, 385129-132, 653/86
• US Class Current: 385/129
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: C25F 3/12 of semiconducting materials
• CPC Class Codes: G02B 2006/12097 Ridge, rib or the like
• CPC Class Codes: G02B 2006/12145 Switch
• CPC Class Codes: G02B 2006/12147 Coupler
• CPC Class Codes: G02B 2006/12159 Interferometer
• CPC Class Codes: G02B 2006/12195 Tapering
• CPC Class Codes: G02B 6/122 Basic optical elements, e.g. light-guiding paths
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: G02F 1/01791 Quantum boxes or quantum dots
• CPC Class Codes: G02F 1/217 Multimode interference type
• CPC Class Codes: G02F 1/3515 All-optical modulation, gating, switching, e.g. control of a light beam by another light beam G02F1/353, G02F1/37, G02F1/39 take precedence
• CPC Class Codes: G02F 1/3517 using an interferometer
• CPC Class Codes: G02F 1/3521 using a directional coupler
• CPC Class Codes: G02F 1/3556 Semiconductor materials, e.g. quantum wells
• CPC Class Codes: G02F 1/365 in an optical waveguide structure G02F1/377, G02F1/395 take precedence
• CPC Class Codes: G02F 2/006 All-optical wavelength conversion
• CPC Class Codes: G02F 2202/32 Photonic crystals
• CPC Class Codes: G02F 2202/36 : Micro- or nanomaterials
• CPC Class Codes: H01L 29/127 : Quantum box structures
• CPC Class Codes: H01L 29/16 : including, apart from doping materials or other impurities, only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 29/1602 : Diamond
• CPC Class Codes: H01L 33/20 : with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/34 : containing only elements of Group IV of the Periodic Table
• CPC Class Codes: Y10S 977/834 : Optical properties of nanomaterial, e.g. specified transparency, opacity, or index of refraction

Abstract

The invention relates to an optical device. The optical device comprises a waveguide core and a nanocomposite material optically coupled to the waveguide core. The nanocomposite material includes a plurality of quantum dots. The nanocomposite material has a nonlinear index of refraction γ that is at least 10⁻⁹ cm²/W when irradiated with an activation light having a wavelength λ between approximately 3×10⁻⁵ cm and 2×10⁻⁴ cm.

Claims

1. An optical device comprising:

a waveguide core including a portion formed of a nanocomposite material, said nanocomposite material including;

a matrix material; and

a plurality of quantum dots dispersed in said matrix material, a quantum dot of said plurality of quantum dots including a substantially crystalline core that includes a semiconductor material selected from the group consisting of Si and Ge, said quantum dot being substantially defect free such that said quantum dot exhibits photoluminescence with a quantum efficiency that is greater than 10 percent.

2. The optical device of claim 1, further comprising a cladding surrounding said waveguide core.

3. The optical device of claim 1, wherein said waveguide core includes a plurality of portions positioned at respective locations along a longitudinal axis of said waveguide core, said plurality of portions being formed of said nanocomposite material.

4. The optical device of claim 1, wherein said waveguide core is a first waveguide core, said optical device further comprising a second waveguide core optically coupled to said first waveguide core.

5. The optical device of claim 1, wherein said nanocomposite material has a nonlinear index of refraction γ

that is at least 10<sup>−

9</sup> cm²/W when irradiated with light having a wavelength λ

between approximately 3×

10<sup>−

5</sup> cm and 2×

10<sup>−

4</sup> cm.

6. The optical device of claim 5, wherein γ

is at least 10<sup>−

8</sup> cm²/W.

7. The optical device of claim 5, wherein said nanocomposite material has a figure-of-merit that is at least 1, said figure-of-merit being defined as 2γ

/β

λ

, where β

is a two-photon absorption coefficient of said nanocomposite material expressed in cm/W.

8. The optical device of claim 7, wherein said figure-of-merit is at least 1.5.

9. The optical device of claim 1, wherein said matrix material is selected from the group consisting of polymers and glasses.

10. The optical device of claim 1, wherein said nanocomposite material comprises more than 10 percent by weight of said plurality of quantum dots.

11. The optical device of claim 1, wherein said nanocomposite material comprises at least 40 percent by weight of said plurality of quantum dots.

12. The optical device of claim 1, wherein said plurality of quantum dots have a peak size between approximately 1 nm and 100 nm.

13. The optical device of claim 1, wherein said quantum dot further includes a shell surrounding said substantially crystalline core.

14. The optical device of claim 1, wherein said semiconductor material is Si, said shell including an oxide SiO_n with n being between approximately 0 and 2.

15. The optical device of claim 1, wherein said semiconductor material is Ge, said shell including an oxide GeO_n with n being between approximately 0 and 2.

16. The optical device of claim 1, wherein said quantum dot further includes a ligand layer surrounding said substantially crystalline core, said ligand layer including a plurality of surface ligands.

17. The optical device of claim 16, wherein a surface ligand of said plurality of surface ligands includes a first portion and a second portion, said first portion being coupled to said substantially crystalline core, said second portion being chemically compatible with said matrix material to facilitate dispersing said quantum dot in said matrix material.

18. The optical device of claim 1, wherein said quantum efficiency is at least 20 percent.

19. The optical device of claim 1, wherein said quantum efficiency is at least 50 percent.

20. The optical device of claim 1, wherein said semiconductor material is Si, said substantially crystalline core having a diameter between approximately 1 nm and 20 nm.

21. The optical device of claim 1, wherein said semiconductor material is Ge, said substantially crystalline core having a diameter between approximately 1 nm and 50 nm.