geo600: the first application of squeezed light
DESCRIPTION
GEO600: The First Application of Squeezed Light. Roman Schnabel, for the GEO600 group, the Quantum Interferometry Group, and the LSC Albert-Einstein-Institut (AEI) Institut für Gravitationsphysik Leibniz Universität Hannover. Outline. Introduction to Squeezed Light - PowerPoint PPT PresentationTRANSCRIPT
GEO600: The First Application of Squeezed Light
Roman Schnabel, for the GEO600 group, the Quantum Interferometry Group, and the LSC
Albert-Einstein-Institut (AEI)
Institut für Gravitationsphysik
Leibniz Universität Hannover
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23 2
Outline
• Introduction to Squeezed Light
• The first squeezed-light laser for GW detectors
• Sensitivity improvement of GEO600 with squeezed light
• Squeezed light as a key-technology for GW astronomy
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Gravitational Waves
Merging neutron stars. Numerical relativity simulation of gravitational waves emitted from two neutron stars which are about to merge in 4 ms [Rezzolla, AEI].
3
h:
Gravitational wave astronomy requires observatories that can detect h < 10-23 (over a band from e.g. 100Hz - 200Hz)
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Laser
50%
Bea
m
splitt
er
Gravitational Wave Detection
Mirror 1
Mirror 22) Laser light
> km
3) Interference
4) Photo-electric effect
Photo diode
4
Photo-electric currentmodulated at GW frequency
1) Test masses
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Photo-Electric Current
Time intervals
Ph
oto
ns p
er
time
inte
rval
5
N
(No signal, but photon shot noise)
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Photo-Electric Current
6
Time intervals
Ph
oto
ns p
er
time
inte
rval
N
(GW signal?)
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Photon Counting Statistics
Coherent state
€
⇒ ˆ N = N = α2
=10000
Photon number N
Pro
babi
lity
[re
l. un
its]
7
NNNN
N
€
α =100
€
~1
N ~
1
PLaser
Relative shot-noise
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Increasing the Light Power
High power laser
Mirror 1
Mirror 2
Photo diode
Photo-electric current
Heating by light absorption
8
Power-recycling mirror
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Is there a possibility to increase the signal/quantum noise–ratio without increasing the laser power?
9
Yes, by squeezed laser light!
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23 10
Shot-Noise in an Interferometer
Laser
Photo diode
Beam splitter
Mirror
[Caves, Phys. Rev. D 23, 1693 (1981)]
Due to zero point fluctuations(vacuum noise)
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Laser
11
Squeezing the Shot-Noise
Photo diode
Beam splitter
MirrorC. M. Caves (1981):Reduction of quantum noise with squeezed light
[Caves, Phys. Rev. D 23, 1693 (1981)]
Squeezed light laser
FaradayRotator
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Squeezing factor: 3 dB
Squeezing factor: 10 dB
“Squeezed” Counting Statistics
Photon number N
Pro
babi
lity
[re
l. un
its]
12
Noise squeezing
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Photo-Electric Current
Time intervals
Ph
oto
ns p
er
time
inte
rval
13
N
(No signal)
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Photo-Electric Current - Squeezed
Time intervals
Ph
oto
ns p
er
time
inte
rval
14
N
Squeezing the noise of a random process without a measurement!?
Quantum mechanics:Squeezing requires time/energy (and amplitude/phase quadrature) entangled photons
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Squeezing in the Wave Picture
X1
X2 cc
c
+
+
+
+
15
Quadrature squeezing at sideband frequency
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
The GEO600 Squeezed Light Laser
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Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23 17
Standing wave cavity
Generation of Squeezed Light (PDC)
2-nonlinear crystal:MgO:LiNbO3
Pump field inputPump field input(cw, 532nm)(cw, 532nm)
Squeezed field outputSqueezed field output(cw, 1064nm) by parametric (cw, 1064nm) by parametric down-conversion (PDC) down-conversion (PDC)
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
History of Squeezed Light Generation
First squeezed light: [Slusher et al., PRL 55, 2409 (1985)]
Research labs with squeezed light (not complete):
- Kimble (CalTech): teleportation: [Furuzawa et al., SCIENCE 282, 706 (1998)]
- Grangier (Orsay); kitten: [Ourjoumtsev et al., SCIENCE, 312, 83 (2006)]
- Schiller and Mlynek (Konstanz): tomography: [Nature 387, 471 (1997).]
- Bachor and Lam (Canberra): 6dB at 1064nm [J. Opt. B 1, 469 (1999).]
- Leuchs (Erlangen); ~7 dB pulsed [Opt. Lett. 33, 116 (2008).]
- Polzik (Copenhagen), [Neergaard-Nielsen et al., PRL 97, 083604 (2006)]
- Furusawa (Tokyo); 9 dB: [Takeno et al., Opt. Express 15, 4321 (2007).]
- Fabre (Paris), Zhang, Peng (Shanxi);
- Andersen (Copenhagen); Mavalvala (MIT),...
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Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
History of Squeezed Light Generation
Research & development towards the first application of squeezed light
- McClelland (ANU), power-recycling [McKenzie et al., PRL 88, 231102 (2002)]
- McClelland (ANU), audio-band [McKenzie et al., PRL 93, 161105 (2004)]
- RS (LUH), signal-recycling [Vahlbruch et al., PRL 95, 211102 (2005)]
- RS (LUH), control scheme [Vahlbruch et al., PRL 97, 011101 (2006)]
- RS (LUH), full band-width [Vahlbruch et al., New Journal of Phys. 9, 371 (2007)]
- Mavalvala (MIT), suspended mirrors [Goda et al., Nature Phys. 4, 472 (2008)]
- RS (LUH), 10dB [Vahlbruch et al., PRL 100, 033602 (2008)]
- RS (LUH), turn-key source [Vahlbruch et al., CQG 27, 084027 (2010)]
Recent review:
[R.S. et al., Nature Comm. 1:121 doi: 10.1038/ncomms1122 (2010)]
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Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Transport to the GEO600 GW Detector
20
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
GEO600: Squeezed Light in Application
21
Observatory noise without squeezed light
With squeezed light
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23
Laser
22
Squeezing the Shot-Noise (SN) and the Radiation Pressure Noise (PRN)
[Kimble et al., Phys. Rev. D 65, 022002 (2001)]
Squeezed light laser
FaradayRotator
[Jaekel and Reynaud, Europhys. Lett. 13, 301 (1990)]
Filter cavities
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23 23
(SQL)
Shot noise
Radiation pressure
noise
[Jaekel, Reynaud 1990]
QND-Regime
Squeezing SN and RPN
Squeezed Light Input (8dB)
Albert - Einstein- Institut R. Schnabel, LaThuile 2011, March 23 24
Summary
• GEO600 now uses squeezed light and achieves its best ever sensitivity (at shot-noise limited frequencies)
• A real application of entangled photons in squeezed light has been realized
• Squeezing is mature and might become a key-technology in all future GW observatories, such as ET