Creating sharp asymmetric lineshapes in microcavity structures

• US 20030142719A1
• Filed: 01/28/2002
• Published: 07/31/2003
• Est. Priority Date: 01/28/2002
• Status: Active Grant

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Inventors: Fan, Shanhui
• Granted Patent: US 6,819,691 B2
• Time in Patent Office: Days
• US Class Current: 372/108
• 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: G02F 1/011 in optical waveguides, not otherwise provided for in this subclass
• CPC Class Codes: G02F 2201/307 Reflective grating, i.e. Bragg grating
• CPC Class Codes: G02F 2203/055 wavelength filtering
• CPC Class Codes: G02F 2203/15 involving resonance effects, e.g. resonantly enhanced interaction

Abstract

We disclose a new structure that allows the creation of sharp and asymmetric lineshapes in optical microcavity systems. In this structure, the response function can vary from 0% to 100% in a frequency range that is narrower than the full width of the resonance itself. Therefore, an optical switch, based upon this structure, may require far less frequency shift to operate, compared with conventional microcavity-based structures. This method may also be used to improve the sensitivity of optical sensors based upon microcavity structures.

Claims

1. A device for transmitting electromagnetic radiation, comprising:

a waveguide transmitting electromagnetic radiation;

a resonator system adjacent to the waveguide, said resonator system affecting the transmission of electromagnetic radiation in the waveguide; and

at least two elements associated with the waveguide, said elements causing partial reflection of electromagnetic radiation in the waveguide.

2. The device of claim 1, wherein said resonator system supports at least one resonant state with at least one resonance frequency.

3. The device of claim 1, wherein said waveguide and said resonator system are in a photonic crystal.

4. The device of claim 3, wherein said resonator system comprises at least one point defect in said photonic crystal

5. The device of claim 3, wherein said waveguide comprises a line defect in said photonic crystal.

6. The device of claim 1, wherein said waveguide comprises a high index dielectric waveguide surrounded by at least one low-index medium.

7. The device of claim 1, wherein said resonator system comprises at least one high index dielectric region surrounded by at least one low-index medium.

8. The device of claim 1, wherein said resonator system comprises at least one point defect in a one-dimensional, two-dimensional or three-dimensional photonic crystal.

9. The device of claim 1, wherein said at least two elements are located in or adjacent to the waveguide.

10. The device of claim 1, wherein said at least two elements associated with the waveguide generate Fabry-Perot oscillations in the transmission of electromagnetic radiation through the waveguide.

11. The device of claim 10, wherein said resonator system supports at least one resonant state with at least one resonance frequency and is configured such that said resonance frequency does not substantially coincide with a maximum of said Fabry-Perot oscillations.

12. An apparatus for switching or modulating electromagnetic radiation, comprising:

(a) a device comprising;

a waveguide transmitting electromagnetic radiation from a source;

a resonator system adjacent to the waveguide, said resonator system defining at least one resonance frequency, and affecting the transmission of electromagnetic radiation in the waveguide; and

at least two elements associated with the waveguide, said elements causing partial reflection of electromagnetic radiation in the waveguide; and

(b) a mechanism to shift said resonance frequency of said resonator system, and thereby to switch or modulate the transmission of electromagnetic radiation through the waveguide.

13. The apparatus of claim 12, wherein said mechanism comprises shifting said resonance frequency by applying electric field, magnetic field, electric current, or electromagnetic radiation energy.

14. The apparatus of claim 13, wherein said resonator system comprises a nonlinear material.

15. The apparatus of claim 13, wherein said resonator system comprises an electrooptic or semiconductor material.

16. The apparatus of claim 12, wherein said mechanism comprises shifting said resonance frequency by applying heat.

17. The apparatus of claim 12, wherein said resonator system is configured such that said waveguide partially transmits and partially reflects electromagnetic radiation at a predetermined wavelength, wherein the waveguide becomes substantially completely transmissive or completely reflective to radiation at the predetermined wavelength when said mechanism is applied.

18. The apparatus of claim 12, wherein said resonator system is configured such that the waveguide substantially reflects all electromagnetic radiation at a predetermined wavelength, wherein the waveguide becomes substantially completely transmissive to radiation at the predetermined wavelength when said mechanism is applied.

19. The apparatus of claim 12, wherein said resonator system is configured such that the waveguide substantially transmits all electromagnetic radiation at a predetermined wavelength, wherein the waveguide becomes substantially completely reflective to radiation at the predetermined wavelength when said mechanism is applied.

20. The apparatus of claim 12, wherein said resonance frequency is in a microwave or optical wavelength range.

21. The apparatus of claim 12, wherein said resonator system supports at least one resonant state with at least one resonance frequency.

22. The apparatus of claim 12, wherein said waveguide and said resonator system are in a photonic crystal.

23. The apparatus of claim 22, wherein said resonator system comprises at least one point defect in said photonic crystal

24. The apparatus of claim 22, wherein said waveguide comprises a line defect in said photonic crystal.

25. The apparatus of claim 12, wherein said waveguide comprises a high index dielectric waveguide surrounded by at least one low-index medium.

26. The apparatus of claim 12, wherein said resonator system comprises at least one high index dielectric region surrounded by at least one low-index medium.

27. The apparatus of claim 12, wherein said resonator system comprises at least one point defect in a one-dimensional, two-dimensional or three-dimensional photonic crystal.

28. The apparatus of claim 12, wherein said at least two elements are located in or adjacent to the waveguide.

29. The apparatus of claim 12, wherein said at least two elements associated with the waveguide generate Fabry-Perot oscillations in the transmission of electromagnetic radiation through the waveguide.

30. The apparatus of claim 29, wherein said resonator system supports at least one resonant state with at least one resonance frequency and is configured such that said resonance frequency does not substantially coincide with a maximum of said Fabry-Perot oscillations.

31. An apparatus for detecting a substance, comprising:

(a) a device comprising;

a waveguide transmitting electromagnetic radiation from a source;

a resonator system adjacent to the waveguide, said resonator system defining at least one resonance frequency, and affecting the transmission of electromagnetic radiation in the waveguide; and

at least two elements associated with the waveguide, said elements causing partial reflection of electromagnetic radiation in the waveguide; and

(b) an instrument detecting transmission or reflection of electromagnetic radiation through the waveguide.

32. The apparatus of claim 31, wherein said substance shifts said resonance frequency, resulting in significant variation of transmission or reflection in said waveguide.

33. The apparatus of claim 31, wherein said resonator system supports at least one resonant state with at least one resonance frequency.

34. The apparatus of claim 31, wherein said waveguide and said resonator system are in a photonic crystal.

35. The apparatus of claim 34, wherein said resonator system comprises at least one point defect in said photonic crystal.

36. The apparatus of claim 34, wherein said waveguide comprises a line defect in said photonic crystal.

37. The apparatus of claim 31, wherein said waveguide comprises a high index dielectric waveguide surrounded by at least one low-index medium.

38. The apparatus of claim 31, wherein said resonator system comprises at least one high index dielectric region surrounded by at least one low-index medium.

39. The apparatus of claim 31, wherein said resonator system comprises at least one point defect in a one-dimensional, two-dimensional or three-dimensional photonic crystal.

40. The apparatus of claim 31, wherein said at least two elements are located in or adjacent to the waveguide.

41. The apparatus of claim 31, wherein said at least two elements associated with the waveguide generate Fabry-Perot oscillations in the transmission of electromagnetic radiation through the waveguide.

42. The apparatus of claim 41, wherein said resonator system supports at least one resonant state with at least one resonance frequency and is configured such that said resonance frequency does not substantially coincide with a maximum of said Fabry-Perot oscillations.