1. Using Quantum Photonics to Create Optical Frequency combs Tobias J. Kippenberg

2. The problem of the “whispering gallery”: observation of Lord Rayleigh in St. Paul Cathedral (London)* *L. Rayleigh Acoustic Whispering Gallery Mode

3. A photon storage time of 1 micro-second implies that the Light can travel up to 1 km inside a glass torus! diameter of a human hair ~100 µm

4. Coupling both to-and-from a 80  m microtoroid on a chip taper-microcavity junction exhibits extremely high ideality (coupling losses <0.3%) Pin 40  m 1/R Coupling light into a microresonator Just like a Guitar string has several vibrational modes, an optical microresonator has many optical modes

5. Silica Resonator (1) Using Quantum Photonics to creat frequency combs At high intensities the interaction becomes nonlinear leading to «twin» photon generation Prism Pump laser Energy conservation requires The Nobel Prize in Physics 1981 Nicolaas Bloembergen Nonlinear Optics

6. Generating a frequency comb from a microresonator Optical microresonator Optical fiber Pump laser A frequency comb

7. Comb generation mechanism Twin Photon generation  p2  p1 ss ii

8. Comb Generation Mechanism pp pp ss ii Twin photon generation

9. Der Entstehungsprozess: Zwillingphotonen Twin photon generation

10. Generating a frequency comb in an optical microresonator Optical frequency comb The perfectly equidistant arrangement is called on optical frequency comb

11. Microresonotor frequency comb An octave spanning optical spectrum is generated from a single laser frequency

12. Optical frequency combs Nobel Prize Physics 2005: “for their contributions to the development of laser-based precision spectroscopy, including the optical frequency comb technique" Hz With an optical frequency combs an unknown optical frequency can be determined accurately measured

13. Why are frequency combs interesting? Frequency combs allow to create very accurate optical atomic clocks. Clocks that loose less than 1 second in the age of the universe of 14 Billion years…

14. Mode locked lasers for frequency comb generation Ronald Holtzwarth, TWH October 2005

15. T. Herr et al. Nature Photonics 2012 (July) Frequency combs on a chip MgF 2 More than 1000 comb lines that are perfectly equidistant generated from a single laser…

16. Advantages of microresonator frequency combs Vorteile: -Very compact compact comb generator - The distance between comb teeth is very large

17. Microresonator frequency combs as channel generators Fiber optical communication uses several wavelength that travel down on optical fiber spaced in frequency by ca. >40 GHz

18. Applications of Frequency combs in Telecommunication Today: picture of 4 laser modules to generate 4 channels… Future: A single microresonator can generate > 1000 channels from a single laser

19. Astrophysical spectrometer: searches for exoplanets Microresonator frequency combs can assist to calibrate astrophysical spectrometers

20. 20 First spectrometer calibration with a Microcavity ESO‘s Very Large Telescope (VLT) in Chile X-Shooter spectrometer (in Munich) Microcavity comb spectrum (83 GHz mode spacing) on echelle grating based spectrometer Frequency comb assisted spectrometer calibration X-Shooter Telescope (ESO)

21. Microresonator frequency combs… Applying them in astrophysical planets searches as calibratoin tool.. …applying them in space optical clocks… … enable them to become sources of mid IR radiation used in chemistry or pharmaceutical minitoring.... Linking RF to optical on a chip…

22. Oktavenspannende Frequenzkaemme Max Planck Institut für Quantenoptik Oktober 2005