Next generation nonclassical light sources for gravitational wave detectors

1. Next generation nonclassical light sourcesfor gravitational wave detectors Stefan Ast, Christoph Baune, Jan Gniesmer, Axel Schönbeck, Christina Vollmer, Moritz Mehmet, Henning Vahlbruch, Hartmut Grote, Lisa Kleybolte, Alexander Khalaidovski and Roman Schnabel Institut für Laserphysik, Universität Hamburg Albert-Einstein-Institut, Max-Planck-Institut für Gravitationsphysik Institut für Gravitationsphysik der Leibniz Universität Hannover Rencontres de Moriond 2015

2. The GEO 600 squeezed light source The LIGO Scientific Collaboration, “A gravitational wave observatory operating beyond the quantum shot-noise limit”, Nature Physics 7 (2011)

3. The GEO 600 squeezed light source Duty cycle: 85% (2011-2015) Max. 3.7 dB The LIGO Scientific Collaboration, “A gravitational wave observatory operating beyond the quantum shot-noise limit”, Nature Physics 7 (2011)

4. Einstein Telescope I – artistic layout M Punturo et al, “The Einstein Telescope: a third-generation gravitational wave observatory”, Class. Quantum Grav. 27 (2010)

5. Einstein Telescope II – Interferometer designs 1550 nm M Punturo et al, “The Einstein Telescope: a third-generation gravitational wave observatory”, Class. Quantum Grav. 27 (2010)

6. High conversion efficiency second harmonic generation Ast et al. “High-efficiency frequency doubling of continuous-wave laser light“; Optics Letters 36 (2011) No. 17 Rencontres de Moriond 2015

7. Improve SHG conversion efficiency

8. Experimental setup – High conversion second harmonic generation Conversion measurement

9. High efficiency second harmonic generation Power Conversion: 1.1 W (1550 nm) ⟶ 1.05 W (775 nm) Power meter error: 6 % total ⟶ inaccurate! 9

10. SHG pump depletion

11. Doubly-resonant squeezed light source at 1550 nm Kleybolte, Master Thesis 2013 Rencontres de Moriond 2015

12. The GEO 600 squeezed light source

13. Doubly resonant squeezing resonator @ 1550 nm 1 MHz 130 kHz

14. Squeezing measurement in the audio band 12.3 dB Squeezing at 1550 nm & strong enough for third generation GW detectors Mehmet et al. “Squeezed light at 1550 nm with a quantum noise reduction of 12.3 dB“; Optics Express 19 (2011) No. 25

15. Frequency conversion of squeezed light Baune et al. arXiv:1503.02008 Rencontres de Moriond 2015

16. DECIGO & squeezing @ 532 nm Sum Frequency Generation 532 nm Kawamura et al, “The Japanese space gravitational wave antenna: DECIGO”, Class. Quantum Grav. 28 (2011)

17. Experimental setup – frequency conversion of squeezed light

18. Squeezing measurement @ 532 nm 5 dB

19. Summary High-efficiency SHG 95% conversion efficiency @ 1550 nm Doubly resonant squeezed light source Maximum of 10 dB @ 1 MHz 7 dB @ 130 kHz Squeezed light for 3. generation GWD 12.3 dB @ 1550 nm Frequency up-conversion of squeezed light 5 dB @ 532 nm

20. Thank you for your attention!

21. Generation of squeezed light Squeezed bandwidth Parametric down conversion Squeezing bandwidth Pump power enhancement Squeezing enhancement FSR Problem: Rω limits the bandwidth!

22. Squeezed light source without squeezing resonator S. Ast et al, Continuous-wave nonclassical light with gigahertz squeezing bandwidth, Optics letters 37, 2367 (2012)

23. Outline GHz bandwidth quantum states Quantum Key Distribution High-bandwidth quantum state generation GHz bandwidth squeezed light GHz bandwidth entangled light Experiment Squeezed light via the cascaded Kerr effect An Odyssey to Kerr squeezing New experimental approach Cascaded Kerr squeezing Experiment

24. Experimental setup – Squeezed light at 1550 nm

25. Kerr squeezing loss estimation Based on 85 mW pump power at 358 MHz Estimated loss contributions 9.5 dB 61% -2 dB Bow-tie internal loss High 775 nm generation