Methods and systems for introducing electromagnetic radiation into photonic crystals

• US 5,999,308 A
• Filed: 04/01/1998
• Issued: 12/07/1999
• Est. Priority Date: 04/01/1998
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Joannopoulos, John, Nelson, Keith A.
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): BURKE, MARGARET A
• Application Number:
  US09/053,160
• Time in Patent Office: 615 Days
• Field of Search: 372/21, 372/22, 372/23, 372/45, 372/50, 385/2, 385/8, 385/9, 385/14, 359/326, 359/344, 359/332, 359/342, 359/245, 359/248, 359/321, 359/322, 333/219.1, 333/202, 356/345, 356/432
• US Class Current: 359/321
• 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 1/3534 Three-wave interaction, e.g. sum-difference frequency generation G02F1/3532 takes precedence
• CPC Class Codes: G02F 2202/32 Photonic crystals

Abstract

A method for introducing desired electromagnetic radiation into a photonic crystal having a photonic bandgap and at least one defect, wherein the desired electromagnetic radiation has a frequency within the photonic bandgap. The method includes the steps of: delivering source electromagnetic radiation having an electromagnetic frequency outside the photonic bandgap to the defect; and generating the desired electromagnetic radiation at the defect in response to the source electromagnetic radiation.

Claims

1. A method for inducing electromagnetic radiation in a photonic crystal having a periodic variation in dielectric constant sufficient to produce a photonic bandgap for at least one propagation direction and at least one polarization direction, the photonic bandgap defining a frequency range for which electromagnetic radiation at a frequency within the frequency range and having a polarization direction among the at least one polarization direction cannot propagate along the at least one propagation direction, and the photonic crystal having at least one defect in the periodic variation sufficient to support a localized mode of electromagnetic radiation at a frequency within the frequency range of the photonic bandgap, the method comprising the steps of:

delivering electromagnetic radiation having a frequency outside the frequency range of the photonic bandgap to the defect; and

generating electromagnetic radiation having a frequency within the frequency range of the photonic bandgap at the defect in response to the delivered electromagnetic radiation.

2. The method of claim 1, wherein the electromagnetic radiation having a frequency within the frequency range of the photonic bandgap is generated through a non-linear interaction between material in the vicinity of the defect and the delivered electromagnetic radiation.

3. The method of claim 1, wherein the delivered electromagnetic radiation is from a coherent source.

4. The method claim 3, wherein the delivered electromagnetic radiation has a bandwidth greater than the frequency of the generated electromagnetic radiation.

5. The method claim 3, wherein the delivered electromagnetic radiation has a bandwidth greater than 1 THz.

6. The method of claim 2, wherein the non-linear interaction is selected from the group consisting of harmonic generation, sum frequency mixing, difference frequency mixing, optical rectification, electro-optic effect, stimulated Raman scattering, and impulsive stimulated Raman scattering.

7. The method of claim 1, wherein the delivered electromagnetic radiation has a peak intensity greater than 1×

10⁶ W/cm².

8. The method of claim 1, wherein the delivered electromagnetic radiation has a peak intensity greater than 1×

10⁸ W/cm².

9. The method of claim 1, wherein the delivered electromagnetic radiation has a peak intensity greater than 1×

10¹⁰ W/cm².

10. The method of claim 1, wherein the photonic crystal comprises a ferroelectric material.

11. The method of claim 10, wherein the ferroelectric material is selected from the group consisting of PbTiO₃, KNbO₃, LiTaO₃, BaTiO₃, KTN, PZT, and PLZT.

12. The method of claim 1, wherein the defect is a void.

13. The method of claim 12, further comprising filling the void with index-matching fluid for the source electromagnetic radiation to prevent scattering of the source electromagnetic radiation.

14. The method of claim 1, wherein the frequency of the delivered electromagnetic radiation is within the visible and near-infrared region of the electromagnetic spectrum and the frequency of the generated electromagnetic radiation is in the near-infrared and infrared region of the electromagnetic spectrum.

15. The method of claim 1, wherein the at least one defect comprises a series of defects arranged to form a waveguide.

16. The method of claim 1, wherein the at least one defect forms a cavity.

33. The method of claim 1, wherein the periodic variation is sufficient to define a complete photonic bandgap, the complete photonic bandgap defining a frequency range for which electromagnetic radiation at a frequency within the frequency range of the complete photonic bandgap cannot propagate within the photonic crystal along any direction away from the at least one defect.

17. An optical system comprising:

a photonic crystal having a periodic variation in dielectric constant sufficient to produce a photonic bandgap for at least one propagation direction and at least one polarization direction, the photonic bandgap defining a frequency range for which electromagnetic radiation at a frequency within the frequency range and having a polarization direction among the at least one polarization direction cannot propagate along the at least one propagation direction, and the photonic crystal having at least one defect in the periodic variation sufficient to support a localized mode of electromagnetic radiation at a frequency within the frequency range of the photonic bandgap; and

a source which during operation delivers electromagnetic radiation having a frequency outside the frequency range of the photonic bandgap to the defect, the delivered radiation generating electromagnetic radiation having a frequency within the frequency range of the photonic bandgap at the defect.

18. The system of claim 17, wherein the at least one defect comprises a series of defects arranged to form a waveguide within the photonic crystal, wherein during operation the generated electromagnetic radiation propagates along the waveguide.

19. The system of claim 18, wherein the delivered electromagnetic radiation generates the electromagnetic radiation having a frequency within the frequency range of the photonic bandgap through a non-linear interaction with material in the vicinity of the defects.

20. The system of claim 18, further comprising a device connected to the waveguide and responsive to the generated electromagnetic radiation propagating along the waveguide.

21. The system of claim 17, wherein the at least one defect forms a cavity within the photonic crystal.

22. The system of claim 21, wherein the delivered electromagnetic radiation generates the electromagnetic radiation having a frequency within the frequency range of the photonic bandgap through a non-linear interaction with material in the vicinity of the cavity.

23. The system of claim 21, wherein electromagnetic energy from the generated electromagnetic radiation tunnels from the cavity to a surface of the photonic crystal and emerges as propagating electromagnetic radiation.

34. The system of claim 17, wherein the periodic variation is sufficient to define a complete photonic bandgap, the complete photonic bandgap defining a frequency range for which electromagnetic radiation at a frequency within the frequency range of the complete photonic bandgap cannot propagate within the photonic crystal along any direction away from the at least one defect.

24. A method for detecting electromagnetic radiation confined in a photonic crystal, the photonic crystal having a periodic variation in dielectric constant sufficient to produce a photonic bandgap for at least one propagation direction and at least one polarization direction, the photonic bandgap defining a frequency range for which electromagnetic radiation at a frequency within the frequency range and having a polarization direction among the at least one polarization direction cannot propagate along the at least one propagation direction, and the confined radiation having a frequency within the frequency range of the photonic bandgap and being confined to at least one defect in the periodic variation, the method comprising the steps of:

directing probe electromagnetic radiation having a frequency outside the frequency range of the photonic bandgap toward the defect;

generating signal electromagnetic radiation that has a frequency outside the frequency range of the photonic bandgap through an interaction between the probe electromagnetic radiation, the confined electromagnetic radiation, and material in the vicinity of the defect; and

detecting the signal electromagnetic radiation to indicate the presence of the confined electromagnetic radiation.

25. The method of claim 24, wherein the interaction is a non-linear interaction.

26. The method of claim 25, wherein the non-linear interaction is selected from the group consisting of harmonic generation, sum frequency mixing, difference frequency mixing, optical rectification, electro-optic effect, stimulated Raman scattering, impulsive stimulated Raman scattering, and optical Kerr effect.

27. The method of claim 24, wherein the probe electromagnetic radiation has a peak intensity greater than 1×

10⁶ W/cm².

28. The method of claim 24, wherein the probe electromagnetic radiation is delivered from a coherent source.

29. The method of claim 24, wherein the at least one defect comprises a series of defects arranged to form a waveguide.

30. The method of claim 24, wherein the at least one defect forms a cavity.

31. The method of claim 24, wherein the detecting step comprises detecting a heterodyne signal.

32. The method of claim 24, wherein the detecting step comprises detecting a heterodyne signal produced from heterodyned optical Kerr effect.

35. The method of claim 24, wherein the periodic variation is sufficient to define a complete photonic bandgap, the complete photonic bandgap defining a frequency range for which electromagnetic radiation at a frequency within the frequency range of the complete photonic bandgap cannot propagate within the photonic crystal along any direction away from the at least one defect.