1 / 17

Optical microcavites

Optical microcavites. Itoh Lab. Yasuhiko Saito. Kerry J. Vahala Nature 424 , 839 (2003). Outline. Introduction Microcavities Whispering gallery mode Application of microcavities Microtoroid ultra high Q cavities Fiber-coupled microsphere laser Summary.

darius
Download Presentation

Optical microcavites

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Optical microcavites Itoh Lab. Yasuhiko Saito Kerry J. Vahala Nature 424, 839 (2003)

  2. Outline Introduction Microcavities Whispering gallery mode Application of microcavities Microtoroid ultra high Q cavities Fiber-coupled microsphere laser Summary

  3. Microcavities Optical microcavities confine light to small volumes by resonant recirculation. Microcavities have the high Q factor and the low volume. Fabry-perot Whispering gallery Photonic crystal High Q Ultra high Q

  4. Q factor In optical region, the Q factor is used for a measure of the photon lifetime. : photon lifetime : mode frequency The Q factor is high. Cavities confine the light efficiently.

  5. Application Optical capacitor, low threshold micro laser, quantum informatics etc. Whispering gallery mode (WGM) In dielectric micro particles, light undergoes total internal reflection at the particle surface and becomes confined within the particles. Example of WGM Minimal reflection loss High Q factor :Refractive index Microsphere, microtoroid, microdisk, droplet

  6. Shape of WGM microcavities WGM microcavities confine light by reflection. The surface is important. Microdisk Microsphere The surface of microspheres and droplets is so smooth that the Q factor is very high. Microtoroid Hexagonal

  7. Input and output High Q cavities can confine light strongly. • Fiber taper • Prism • Waveguide Difficult for input and output. Various ways are attempted… J. C. Knight. et al. optics letters. 22, 15 (1997). Fiber tapers are best way to contact with cavities.

  8. About this study Microsphere laser The authors fabricated the laser by the glass microsphere and fiber taper. Ultra high Q toroidal microcavities They attempted to get the ultra high Q factor in the microtoroid.

  9. Fiber-coupled microsphere laser Pump wave Benefit Easy to fabricate smooth surface Fiber taper Emission wave Defect Difficult to control the size Phosphate glass ( ) microsphere Er:Yb doped for amplification

  10. Fiber-coupled microsphere laser Photoluminescence spectra Diameter 57μｍ Pump wave 980nm Depending on the gain region within the sphere, lasing occurred at wavelengths ranging from 1530 to 1560 nm. M. Cai et al. OPTICS LETTERS. 25. 19 (2000)

  11. Fiber-coupled microsphere laser Output laser power Threshold 60μW

  12. Microtoroid ultra high Q cavities Silica toroid Benefit It can be made on the chip. Silicon post Defect Difficult to fabricate and to control the surface Q factor : Lower than microshperes Fiber taper

  13. Microtoroid ultra high Q cavities Fabrication process Photo lithography (Fabricating circular pad) Dry etching (Etching the silicon) D. K. Armani et al. Nature. 421. 925 (2003) Reflow (Melting the disk along the periphery)

  14. Microtoroid ultra high Q cavities Photon lifetime measurement τ＝43ns

  15. 500nｍ My works We succeeded to fabricate ZnO microsphere by laser ablation in superfluid helium. Laser ablation ZnO tablet laser

  16. My works Cathodoluminescence of the ZnO microsphere The WGM is observed. 500nｍ Spectra of the ZnO microsphere futurework Attempt to laser oscillation Manipulating microsphere General spectrum of ZnO

  17. Summary • Microcavities can confine light to small volumes effectively. • Laser oscillation was observed by the photoluminescence in the microsphere. • The authors succeeded to fabricate ultra high Q microtroid cavities.

More Related