Next generation nonclassical light sources for gravitational wave

Next generation nonclassical light sources for 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 der Leibniz Universität Hannover Rencontres de Moriond 2015

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) Stefan Ast 2

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

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

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) Stefan Ast 5

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

Improve SHG conversion efficiency Stefan Ast 7

Experimental setup – High conversion second harmonic generation Conversion measurement Stefan Ast 8

High efficiency second harmonic generation Power Conversion: 1. 1 W (1550 nm) ⟶ 1. 05 W (775 nm) Power meter error: 6 % total ⟶ inaccurate! Stefan Ast 9 9

SHG pump depletion Stefan Ast 10

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

The GEO 600 squeezed light source Stefan Ast 12

Doubly resonant squeezing resonator @ 1550 nm 1 MHz 130 k. Hz Stefan Ast 13

Squeezing measurement in the audio band 12. 3 d. B 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 d. B“; Optics Express 19 (2011) No. 25 Stefan Ast 14

Frequency conversion of squeezed light Baune et al. ar. Xiv: 1503. 02008 Rencontres de Moriond 2015

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

Experimental setup – frequency conversion of squeezed light Stefan Ast 17

Squeezing measurement @ 532 nm 5 d. B Stefan Ast 18

Summary High-efficiency SHG 95% conversion efficiency @ 1550 nm Doubly resonant squeezed light source Maximum of 10 d. B @ 1 MHz 7 d. B @ 130 k. Hz Squeezed light for 3. generation GWD 12. 3 d. B @ 1550 nm Frequency up-conversion of squeezed light 5 d. B @ 532 nm Stefan Ast 19

Thank you for your attention! Stefan Ast 20

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

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

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 Stefan Ast 23

Experimental setup – Squeezed light at 1550 nm Stefan Ast 24

Kerr squeezing loss estimation Based on 85 m. W pump power at 358 MHz 9. 5 d. B Estimated loss contributions Type 61% Homodyne efficiency 0. 978 PD quantum efficiency 0. 94 Optical path loss -2 d. B Detection efficiency 0. 88 -0. 92 Bow-tie internal loss 0. 547 SEMC transmission 0. 887 Total 0. 39 -0. 41 Bow-tie internal loss High 775 nm generation Stefan Ast 25