Resonant cavities employing two dimensionally periodic dielectric materials

• US 5,784,400 A
• Filed: 02/28/1995
• Issued: 07/21/1998
• Est. Priority Date: 02/28/1995
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Joannopoulos, John D., Meade, Robert D.
• Primary Examiner(s): Bovernick, Rodney B.
• Assistant Examiner(s): Song, Yisun
• Application Number:
  US08/395,441
• Time in Patent Office: 1,239 Days
• Field of Search: 372/96, 372/39, 372/49, 372/99, 372/92, 372/50, 343/909, 359/344
• US Class Current: 372/96
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: H01S 5/10 Construction or shape of the optical resonator , e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region H01S5/20 takes precedence
• CPC Class Codes: H01S 5/1042 Optical microcavities, e.g. cavity dimensions comparable to the wavelength
• CPC Class Codes: H01S 5/11 Comprising a photonic bandgap structure

Abstract

The present invention provides a resonant cavity including a planar two-dimensional periodic dielectric structure which exhibits a photonic band gap and a defect in the periodic dielectric structure which results in an electromagnetic mode within the photonic band gap. The photonic band gap effects an in-plane spacial confinement of electromagnetic radiation generated within the structure. The electromagnetic radiation is vertically confined by total internal reflection.

Claims

1. A resonant cavity comprising:

a planar two-dimensionally periodic dielectric structure which exhibits a two-dimensional photonic bandgap for propagation of radiation having a spectrum of electromagnetic modes in any direction in the plane of said structure; and

a defect in said two-dimensionally periodic dielectric structure which results in an electromagnetic mode localized in the vicinity of said defect within said photonic bandgap, wherein

said photonic bandgap effects an in-plane spacial confinement of electromagnetic radiation for any direction of propagation of said electromagnetic radiation in the plane of said structure, said electromagnetic radiation being vertically confined by total internal reflection.

2. The resonant cavity of claim 1, wherein a waveguide is provided within said two-dimensionally periodic dielectric structure in the proximity of said defect.

3. The resonant cavity of claim 2, wherein said waveguide is supported by a substrate, said substrate providing a refractive index contrast with said waveguide.

4. The resonant cavity of claim 1, wherein said structure comprises a two-dimensional array of holes provided therein for periodicity.

5. The resonant cavity of claim 4, wherein said local defect comprises a region in which at least one of said holes is varied in size with respect to the remaining holes in said array.

6. The resonant cavity of claim 1, wherein said structure comprises an array of rods extending therefrom for periodicity.

7. The resonant cavity of claim 6, wherein said defect comprises a region in which at least one of said rods is varied in size or dielectric constant with respect to the remaining rods in said array.

8. The resonant cavity of claim 7, wherein each of said array of rods includes a first portion comprising a material having a first dielectric constant and a second portion comprising a material having a differing second dielectric constant.

9. A resonant cavity which exhibits an electromagnetic mode for use in a microlaser, comprising:

a planar two-dimensionally periodic dielectric structure which exhibits a two-dimensional photonic bandgap for propagation of radiation having a spectrum of electromagnetic modes in any direction in the plane of said structure, said structure vertically confines radiation by total internal reflection; and

a local defect disposed in said two-dimensionally periodic dielectric structure which results in an electromagnetic mode localized in the vicinity of said defect, said local defect accommodating an in-plane spacial confinement of said radiation for any direction of propagation of said radiation in the plane of said structure.

10. The resonant cavity of claim 9, wherein a waveguide is provided within said two-dimensionally periodic dielectric structure in the proximity to said defect.

11. The resonant cavity of claim 10, wherein said waveguide is supported by a substrate, said substrate providing a refractive index contrast with said waveguide.

12. The resonant cavity of claim 9, wherein said structure comprises an array of holes provided therein for periodicity.

13. The resonant cavity of claim 12, wherein said defect comprises a region in which at least one of said holes is varied in size with respect to the remaining holes in said array.

14. The resonant cavity of claim 9, wherein said structure comprises an array of rods extending therefrom for periodicity.

15. The resonant cavity of claim 14, wherein said defect comprises a region in which at least one of said rods is varied in size or dielectric constant with respect to the remaining rods in said array.

16. The resonant cavity of claim 15, wherein each of said array of rods includes a first portion comprising a material having a first dielectric constant and a second portion comprising a material having a differing second dielectric constant.

17. A method of producing a resonant cavity with enhanced radiation confinement, comprising:

providing a substrate;

forming a planar two-dimensionally periodic dielectric structure which exhibits a two-dimensional photonic bandgap on said substrate, said photonic band gap effecting an in-plane spacial confinement of electromagnetic radiation for any direction of propagation of said electromagnetic radiation in the plane of said structure, said electromagnetic radiation being vertically confined by total internal reflection and

forming a defect in said two-dimensionally periodic structure which results in an electromagnetic mode within said photonic bandgap, and which accommodates spacial confinement of radiation generated within said structure.

18. A device comprising:

a resonant cavity including a planar two-dimensionally periodic dielectric structure which exhibits a two-dimensional photonic bandgap, and a defect in said structure which results in an electromagnetic mode localized in the vicinity of said defect within said photonic bandgap, wherein said photonic band gap effects an in-plane spacial confinement of electromagnetic radiation for any direction of propagation of said electromagnetic radiation in the plane of said structure, said electromagnetic radiation being vertically confined by total internal reflection; and

a waveguide integrated within said two-dimensionally periodic dielectric structure in the proximity of said defect, said waveguide serving to channel portions of said electromagnetic radiation generated by said resonant cavity.

19. The device of claim 18, wherein at least one additional waveguide is integrated within said structure in the proximity of said defect.

20. A resonant cavity device for use in a filter, comprising:

a resonant cavity including a planar two-dimensionally periodic dielectric structure which exhibits a two-dimensional photonic bandgap, and a defect in said structure which results in an electromagnetic mode localized in the vicinity of said defect within said photonic bandgap, wherein said photonic bandgap effects an in-plane spacial confinement of electromagnetic radiation for any direction of propagation of said electromagnetic radiation in the plane of said structure, said electromagnetic radiation being vertically confined by total internal reflection; and

a first waveguide integrated within said two-dimensinally periodic dielectric structure in the proximity of said defect, said first waveguide serving to channel portions of said electromagnetic radiation generated by said resonant cavity; and

a second waveguide integrated within said two-dimensionally periodic dielectric structure in the proximity of said defect, said second waveguide serving to channel electromagnetic radiation into said resonant cavity.