1. S. ChelkowskiSlide 1WG1 Meeting, Birmingham 07/2008

2. Overview  Quantum noise in gravitational wave detectors  Generation of squeezed states  Using squeezing in a gravitational wave detector  Frequency dependent squeezing  Generation of squeezing in the gravitational wave frequency band  Best squeezing measurements so far  Squeezed light in GEO600 S. ChelkowskiWG1 Meeting, Birmingham 07/2008Slide 2

3. A simple gravitational wave detector 3S. ChelkowskiWG1 Meeting, Birmingham 07/2008

4. S. ChelkowskiWG1 Meeting, Birmingham 07/20084 Quantum noise limited sensitivity Shot NoiseRadiation Pressure Noise factor 100 in power = factor 10 in sensitivity = factor 1000 in event rate

5. S. ChelkowskiWG1 Meeting, Birmingham 07/20085 Squeezed light enhanced interferometer

6. S. ChelkowskiWG1 Meeting, Birmingham 07/20086 Squeezed light enhanced interferometer 20dB of squeezing = factor 10 in sensitivity = factor 1000 in event rate

7. S. ChelkowskiWG1 Meeting, Birmingham 07/20087 Amplitude-Quadrature Phase-Quadrature Heisenberg uncertainty relation An explanation of squeezing coherent state squeezed state

8. S. ChelkowskiWG1 Meeting, Birmingham 07/20088 Vacuum Noise

9. S. ChelkowskiWG1 Meeting, Birmingham 07/20089 Squeezed Vacuum

10. S. ChelkowskiWG1 Meeting, Birmingham 07/200810 Strong interaction between seed- and pump field MgO:LiNbO 3 – crystal as nonlinear material Phase matching via temperature Fractions in phase get amplified, out of phase deamplified OPA - optical parametric amplification 1064nm532nm

11. S. ChelkowskiWG1 Meeting, Birmingham 07/200811 MgO:LiNbO3 2 x 2.5 x 6.5mm 7% doping bikonvex or plane/konvex rc=8mm coatings @ 1064 and 532nm Side A: AR (R < 0.05%) Side B: HR (R > 99.98%) hemilithic Resonator @ 1064nm coupling mirror R = 96.7% Finesse = 180 FSR = 3.9GHz phasematching temp. ~65°C temp. stabilized via peltier elements New oven design

12. S. ChelkowskiWG1 Meeting, Birmingham 07/200812 Dark Noise Broadband squeezing up to 30MHz Relaxation oscillation of the Laser Vacuum noise Squeezing results from a normal OPA

13. Squeezing in a real gravitational wave detector S. ChelkowskiWG1 Meeting, Birmingham 07/2008Slide 13

14. S. ChelkowskiWG1 Meeting, Birmingham 07/200814 GEO600

15. S. ChelkowskiWG1 Meeting, Birmingham 07/200815 Quantum noise in GEO600

16. S. ChelkowskiWG1 Meeting, Birmingham 07/200816 Reducing the quantum noise

17. S. ChelkowskiWG1 Meeting, Birmingham 07/200817 68% amplitude squeezing Reducing the quantum noise

18. S. ChelkowskiWG1 Meeting, Birmingham 07/200818 Reducing the quantum noise

19. S. ChelkowskiWG1 Meeting, Birmingham 07/200819 Effect of a detuned filter cavity Squeezed Vacuum Interaction with a cavity

20. S. ChelkowskiWG1 Meeting, Birmingham 07/200820 amplitude squeezing +45°-45° Reducing the quantum noise

21. S. ChelkowskiWG1 Meeting, Birmingham 07/200821 Reducing the quantum noise

22. Frequency-dependent squeezed light How can we create it? S. ChelkowskiWG1 Meeting, Birmingham 07/2008Slide 22

23. S. ChelkowskiWG1 Meeting, Birmingham 07/200823 Chelkowski et al.,PRA 71, 013806 (2005) Frequency-dependent squeezing 67% Detuned locked to +15MHz

24. S. ChelkowskiWG1 Meeting, Birmingham 07/200824 Chelkowski et al.,PRA 71, 013806 (2005) Squeezing Vacuum Noise Anti-Squeezing Phase quadrature Amplitude quadrature Frequency-dependent squeezing

25. A rotating squeezing ellipse – FC detuning +15MHz S. ChelkowskiWG1 Meeting, Birmingham 07/200825 Chelkowski et al.,PRA 71, 013806 (2005)

26. A rotating squeezing ellipse – FC detuning +15MHz S. ChelkowskiWG1 Meeting, Birmingham 07/200826 Chelkowski et al.,PRA 71, 013806 (2005)

27. S. ChelkowskiWG1 Meeting, Birmingham 07/200827 Chelkowski et al.,PRA 71, 013806 (2005) +15 MHz -15 MHz Angle of the squeezing ellipse

28. Generation of squeezed light on the gravitational wave frequency band S. ChelkowskiWG1 Meeting, Birmingham 07/2008Slide 28

29. S. ChelkowskiWG1 Meeting, Birmingham 07/200829 Generic squeezing from an OPA Dark Noise broadband Squeezing up to 30MHz Relaxation oscillation of the Lasers Vacuum noise

30. S. ChelkowskiWG1 Meeting, Birmingham 07/200830 Seed field carries technical noise from the laser. Technical noise is imprinted onto the squeezed field. Seed field is needed for the generation of error signals. OPA – optical parametric amplification

31. S. ChelkowskiWG1 Meeting, Birmingham 07/200831 Seed field is a control field

32. S. ChelkowskiWG1 Meeting, Birmingham 07/200832 OPA without seed turns into an OPO

33. S. ChelkowskiWG1 Meeting, Birmingham 07/200833 Setup for low frequency squeezing   homodyne angle squeezing angle

34. S. ChelkowskiWG1 Meeting, Birmingham 07/200834  Setup for low frequency squeezing  homodyne angle squeezing angle

35. S. ChelkowskiWG1 Meeting, Birmingham 07/200835 Setup for low frequency squeezing    homodyne angle squeezing angle

36. S. ChelkowskiWG1 Meeting, Birmingham 07/200836 Setup for low frequency squeezing   homodyne angle squeezing angle 

37. Measured vacuum noise 37 vacuum noise for 176µW vacuum noise for 88µW vacuum noise for 44µW 3dB S. ChelkowskiWG1 Meeting, Birmingham 07/2008

38. Measured squeezed vacuum noise 38 vacuum noise for 88µW squeezed vacuum noise Chelkowski et al., PRA 75, 043814 (2007) ~6dB S. ChelkowskiWG1 Meeting, Birmingham 07/2008

39. Squeezed vacuum enhanced Michelson interferometer S. ChelkowskiWG1 Meeting, Birmingham 07/200839

40. Best squeezing measurements so far S. ChelkowskiWG1 Meeting, Birmingham 07/2008Slide 40

41. Optical layout S. ChelkowskiWG1 Meeting, Birmingham 07/2008Slide 41 Vahlbruch et al. PRL 100, 033602 (2008)

42. Measured squeezing S. ChelkowskiWG1 Meeting, Birmingham 07/2008Slide 42 Vahlbruch et al. PRL 100, 033602 (2008)

43. Squeezed light in GEO600 S. ChelkowskiWG1 Meeting, Birmingham 07/2008Slide 43

44. S. ChelkowskiWG1 Meeting, Birmingham 07/200844 GEO HF: Detuned Signal Recycling

45. S. ChelkowskiWG1 Meeting, Birmingham 07/200845 GEO HF: Tuned Signal Recycling

46. S. ChelkowskiWG1 Meeting, Birmingham 07/200846 Do we need a filter cavity?

47. Conclusion  Squeezed light can be used to reduces the quantum noise in gravitational wave detectors  Reflection at a detuned cavity creates frequency dependent light  Without a filter cavity, tuned signal recycling is the best choice  All needed techniques for the implementation of squeezed light into a gravitational wave detector are developed S. ChelkowskiWG1 Meeting, Birmingham 07/2008Slide 47

48. Appendix S. ChelkowskiWG1 Meeting, Birmingham 07/2008Slide 48

49. 49 GEO 600 Layout GEO 600:

50. 50 3dB SQZ: 6dB SQZ: GEO HF Layout: short 8m Filter Cavity

51. 51 3dB SQZ: 6dB SQZ: GEO HF Layout: long 1200m Filter Cavity