CREATING PHOTON ATOMS

• US 20040017834A1
• Filed: 07/23/2002
• Published: 01/29/2004
• Est. Priority Date: 07/23/2002
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Bawendi, Moungi G., Joannopoulos, John D., Sundar, Vikram C., Ibanescu, Mihai
• Granted Patent: US 7,319,709 B2
• Time in Patent Office: Days
• US Class Current: 372/39
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01S 3/0604 in the form of a plate or disc
• CPC Class Codes: H01S 3/0627 the resonator being monolithic, e.g. microlaser
• CPC Class Codes: H01S 3/16 Solid materials
• CPC Class Codes: H01S 3/168 using an organic dye dispersed in a solid matrix
• CPC Class Codes: H01S 3/169 Nanoparticles, e.g. doped nanoparticles acting as a gain material
• CPC Class Codes: H01S 5/1042 Optical microcavities, e.g. cavity dimensions comparable to the wavelength

Abstract

A narrow linewidth fluorescent emitter can incorporate a chromophore into a microcavity that can support low-order optical modes.

Claims

1. A fluorescent emitter comprising:

a core including a chromophore defining an emission profile; and

a plurality of dielectric layers surrounding the core, each layer having a thickness and a refractive index such that the plurality of dielectric layers causes at least a portion of the emission profile to narrow upon passing through the plurality of dielectric layers.

2. A photonic structure comprising:

a core which in isolation defines a density of states for allowed modes of electromagnetic radiation; and

a plurality of dielectric layers surrounding the core, each layer having a thickness and refractive index such that the plurality of dielectric layers causes the density of states to narrow.

3. The structure of claim 2, wherein the core comprises at least one chromophore defining an emission profile.

4. The structure of claim 3, wherein the plurality of dielectric layers causes at least a portion of the emission profile to narrow upon passing through the plurality of layers.

5. The structure of claim 3, wherein the chromophore comprises a semiconducting nanoparticle.

6. The structure of claim 3, wherein the chromophore comprises a dye molecule.

7. The structure of claim 3, wherein the chromophore comprises an inorganic phosphor.

8. The structure of claim 2, wherein the core is substantially spherical.

9. The structure of claim 8, wherein the core comprises silica.

10. The structure of claim 8, wherein the core comprises a polymer.

11. The structure of claim 2, further comprising a metallic layer surrounding the plurality of dielectric layers.

12. The structure of claim 11, further comprising one or more additional dielectric layers surrounding the metallic layer.

13. The structure of claim 2, wherein the refractive index of a first layer of the plurality is greater than the refractive index of a second layer of the plurality, the second layer being adjacent to the first layer.

14. The structure of claim 13, wherein the first layer comprises a transition metal oxide and an inorganic sulfide.

15. The structure of claim 13, wherein the second layer comprises silica.

16. The structure of claim 13, wherein the first layer and the second layer alternate through the plurality of layers.

17. The structure of claim 2, wherein the core and the plurality of dielectric layers define at least one resonant cavity having a Q factor greater than 40 for at least one selected wavelength.

18. The structure of claim 2, wherein the core and the plurality of dielectric layers define at least one resonant cavity having a Q factor greater than 100 for at least one selected wavelength.

19. The structure of claim 4, wherein the chromophore defines an absorption profile, and wherein electromagnetic radiation sufficient to be absorbed by a portion of the absorption profile can be transmitted through the plurality of dielectric layers.

20. The structure of claim 2, wherein the plurality of dielectric layers comprises a bilayer, the bilayer having a first layer having a refractive index greater than the refractive index of a second layer.

21. The structure of claim 20, wherein the plurality of dielectric layers comprises a plurality of bilayers.

22. The structure of claim 2, wherein the core comprises a nonlinear optical material which in response to an optical excitation sufficiently changes its refractive index to prevent the narrowing of the density of states by the plurality of dielectric layers.

23. A photonic superstructure comprising a plurality of photonic structures,

wherein each photonic structure comprises

a core which in isolation defines a density of states for allowed modes of electromagnetic radiation;

and

a plurality of dielectric layers surrounding the core, each layer having a thickness and refractive index such that the plurality of dielectric layers causes the density of states to narrow, and wherein the photonic structures are sufficiently close to one another to couple their allowed modes of electromagnetic radiation.

24. The photonic superstructure of claim 23, wherein the superstructure is a self-assembly of the plurality of photonic structures.

25. The photonic superstructure of claim 23, wherein the superstructure further comprises a substrate that supports an assembly of the plurality of photonic structures.

26. The photonic superstructure of claim 25, wherein the substrate is patterned.

27. A light emitting display comprising:

a plurality of narrow-linewidth, fluorescent emitters, wherein each emitter comprises

a core including a chromophore defining an emission profile; and

a plurality of dielectric layers surrounding the core each layer having a thickness and a refractive index such that the plurality of dielectric layers causes at least a portion of the emission profile to narrow upon passing through the plurality of the dielectric layers.

28. A laser comprising:

a gain medium comprising a plurality of narrow-linewidth, fluorescent emitters, wherein each emitter comprises;

a core including a chromophore defining an emission profile; and

a plurality of dielectric layers surrounding the core each layer having a thickness and a refractive index such that the plurality of dielectric layers causes at least a portion of the emission profile to narrow upon passing through the plurality of the dielectric layers;

a pumping source arranged to excite a population inversion in the gain medium; and

an optical cavity surrounding the gain medium.

29. A method of making a photonic structure comprising:

providing a core defining a density of states for allowed modes of electromagnetic radiation, and

surrounding the core with a plurality of dielectric layers capable of narrowing at least a portion of the density of states.

30. The method of claim 29, wherein surrounding the core comprises depositing a first layer on the core having a first refractive index followed by depositing a second layer having a second refractive index greater than the second refractive index.

31. The method of claim 29, further comprising doping the core with a chromophore.