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 HamburgAlbert-Einstein-Institut, Max-Planck-Institut für Gravitationsphysik

Institut für Gravitationsphysik der Leibniz Universität Hannover

Rencontres de Moriond2015

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Stefan Ast

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)

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Stefan Ast

The GEO 600 squeezed light source

Max. 3.7 dB

Duty cycle:85% (2011-2015)

The LIGO Scientific Collaboration, “A gravitational wave observatory operating beyond the quantum shot-noise limit”, Nature Physics 7 (2011)

4

Stefan Ast

Einstein Telescope I – artistic layout

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

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Stefan Ast

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)

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 Moriond2015

7

Stefan Ast

Improve SHG conversion efficiency

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Stefan Ast

Experimental setup – High conversion second harmonic generation

Conversionmeasurement

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Stefan Ast 9

Power Conversion: 1.1 W (1550 nm) ⟶ 1.05 W (775 nm)

Power meter error: 6 % total ⟶ inaccurate!

High efficiency second harmonic generation

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Stefan Ast

SHG pump depletion

Doubly-resonant squeezed light source at 1550 nm

Rencontres de Moriond2015

Kleybolte, Master Thesis 2013

12

Stefan Ast

The GEO 600 squeezed light source

13

Stefan Ast

Doubly resonant squeezing resonator @ 1550 nm

130 kHz

1 MHz

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Stefan Ast

Squeezing measurement in the audio band

Mehmet et al. “Squeezed light at 1550 nm with a quantum noise reduction of 12.3 dB“;Optics Express 19 (2011) No. 25

12.3 dB

Squeezing at 1550 nm & strong enough for third generation GW detectors

Frequency conversion of squeezed light

Baune et al. arXiv:1503.02008

Rencontres de Moriond2015

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Stefan Ast

DECIGO & squeezing @ 532 nm

Sum Frequency Generation

Kawamura et al, “The Japanese space gravitational wave antenna: DECIGO”,Class. Quantum Grav. 28 (2011)

532 nm

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Stefan Ast

Experimental setup – frequency conversion of squeezed light

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Stefan Ast

Squeezing measurement @ 532 nm

5 dB

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Stefan Ast

Summary

High-efficiency SHG

95% conversion efficiency @ 1550 nm

Doubly resonant squeezed light sourceMaximum of 10 dB @ 1 MHz

7 dB @ 130 kHz

Squeezed light for 3. generation GWD12.3 dB @ 1550 nm

Frequency up-conversion of squeezed light5 dB @ 532 nm

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Stefan Ast

Thank you for your attention!

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Stefan Ast

Problem: Rω limits the bandwidth!

Parametric down conversion

Pump power enhancement

Squeezing enhancement

Generation of squeezed light

Squeezed bandwidth

FSR

Squeezingbandwidth

Finesse∝π√R1−R

FSR=c

2nL

Squeezed light source without squeezing resonator

S. Ast et al, Continuous-wave nonclassical light with gigahertz squeezing bandwidth, Optics letters 37, 2367 (2012)

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Stefan Ast

Outline

GHz bandwidth quantum states

Quantum Key Distribution

High-bandwidth quantum state generation

GHz bandwidth squeezed light

GHz bandwidth entangled light

Squeezed light via the cascaded Kerr effect

An Odyssey to Kerr squeezing

New experimental approach

Cascaded Kerr squeezing

Experiment

Experiment

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Stefan Ast

Experimental setup – Squeezed light at 1550 nm

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Stefan Ast

Kerr squeezing loss estimation

61%

Based on 85 mW pump power at 358 MHz

Type Detection efficiency

Homodyne efficiency 0.978

PD quantum efficiency 0.94

Optical path loss 0.88-0.92

Bow-tie internal loss 0.547

SEMC transmission 0.887

Total 0.39-0.41

Estimated loss contributions

Bow-tie internal lossHigh 775 nm generation

-2 dB

9.5 dB