1. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Optical cavity with high quality factor Q Photonic crystals course final presentation Karin Söderström

2. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström2 Outline 1) Optical cavities and their use (history) 2) Quality factor Q 3) Lots of cavities 4) Applications of Cavities with PHC Quantum optic Frequency selective devices

3. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström3 The simplest optical cavity: A Fabry-Pérot resonator is composed of two parallel mirrors Associated with an active medium this cavity realized with one mirror with R<100% leads to one of the greatest discovery of the century Optical cavities and their use Laser by Th. Maiman Nature 187, 493-494 (1960) Macro-cavity

4. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström4 Optical cavities and their use One of the first study on resonator lead to the theoretical great result: –By placing a two-level system in a resonator you can modify (enhance or stop) the spontaneous emission of the two–level system E.M.Purcell Phys. Rev. 69 (1946) p. 681 This information lead to many hope in different field: –One photon source –Quantum entanglement of radiation and matter is possible Thompson, R. J., Rempe, G. & Kimble, H. J. Phys. Rev. Lett. 68, 1132–1135 (1992). P. Michler, A. Kiraz, C. Becher, W. V. Schoenfeld, P. M. Petroff, Lidong Zhang, E. Hu, and A. Imamoglu (2000) Science 290 (5500), 2282.

5. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström5 Quality factor Q Definition: Q = P in the cavity / P Losses α lifetime photon in the cavity  Q α 1/  where  is the linewidth If R, Q. The quality of the information.

6. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström6 Lots of different cavities Fabry-Pérot cavity made of two Bragg mirrors Cavity made by a defect in a photonic crystal Kerry J. Vahala, Nature, 424, 6950, 839, (2003)

7. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström7 Outline 1) Optical cavities and their use (history) 2) Quality factor Q 3) Lots of cavities 4) Cavities with PHC Quantum optic Frequency selective devices

8. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström8 PHC Cavities Applications Quantum optics: Control of the radiative lifetime (Purcell Effect)F p α Q mode /V mode Painter,O. et al. Science 284, 1819–1821 (1999). Applications: Data transport in optical fiber. Easy writing and reading of CD, DVD (small spot size) Miniature laser, LED, VCSEL,  W threshold Control of the  in a micropillar Solomon et al,Phys.Rev.lett., 86, 17, 3903, (2001). t=1.3ns t=280ps

9. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström9 PHC Cavities Applications Quantum optics: –Strong coupling (of great interest due to the mode volume) single-atom cavity quantum electrodynamics in the strong coupling regime Theoretically proven: Vuckovic et al, Phys. Rev. E, 65, 016608, (2001) Experimentally shown: Yoshie et al, Nature 432, 200-203 (2004) for a QD Applications: Study of center of mass motion: Rempe, Applied physics. B, 60, 233 (1995) Single photon source: B Deveaud-Pledran, et al - US Patent App. 11/394,518, (2006) Beauty of physics BEC Theoretical: E Ostrovskaya, Y Kivshar, Optics Exp. vol12, (2004)

10. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström10 PHC Cavities Applications Frequency devices (the mode volume is less important) Akahane et al, Nature, 425, 6961, 944, (2003) Applications: Very small spectrometer, Multiplexer, Demultiplexer, Filters, Spectroscopy

11. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström11 Frequency devices (V mode is less important, here Q=400) PHC Cavities Applications Applications: Very small spectrometer, Multiplexer, Demultiplexer Noda et al, Nature, 407, 608, (2000) Shinya et al, Optics Exp,14, 25, 12394, (2006)

12. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström12 PHC Cavities Applications Frequency devices (the mode volume is less important) Applications: Filters Kuramochi et al, Appl. Phys. Lett., 88, 041112, (2006) Q th : 7*10^7

13. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström13 PHC Cavities Applications Frequency devices (the mode volume is less important) Application: Spectroscopy tool A photonic crystal sensor with a resolution of better than  n =0.002 with a Q factor of 400 Chow et al, Optics letters, 29, 10, 1093, (2004) In this case it is not a bridge: small amount of sample only needed The Caltech Nanofabrication Group

14. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström14 The cavity is the basis to construct devices with photonic crystals with different functionality modes –Single photon source needed for quantum computation Conclusions Lots of progresses can be made on Q (from theoretical studies) but the limits of the fabrication process can be reached before Lots of different applications in many fields –Laser, spectrometer, multiplexer, filter, spectroscopy

15. IMT INSTITUT DE MICROTECHNIQUE NEUCHÂTEL Karin Söderström15 ?Questions? Thanks for your attention