Generation and Control of Squeezed Light Fields

R. SchnabelS.Chelkowski A.FranzenB.HageH.Vahlbruch

N. LastzkaM.MehmetJ.DiGuglielmoundK. Danzmann

Albert-Einstein-InstitutHannoverMax-Planck-Institut fürGravitationsphysikund

Institut für Gravitationsphysik, Universität Hannover

2Elba, 28.05.2006, Roman Schnabel

Techniques against Shot Noise

Power-Recycling mirror

Laser

Photo diode

RSE / Signal-recycling mirror

Arm cavity

Vacuum (shot) noise

Squeezed vacuum !

3Elba, 28.05.2006, Roman Schnabel

Phase Modulation at 0

€

ℑ(α )

€

δ2(t,Ω0)

=−i

2δα t,ω + Ω0( ) −δα * t,ω − Ω0( )[ ]

€

ℜ(α )

(δ2)

4Elba, 28.05.2006, Roman Schnabel

Amplitude Modulation at 0

€

δ1(t,Ω0)

=1

2δα t,ω + Ω0( ) + δα * t,ω − Ω0( )[ ]

€

ℑ(α )

€

ℜ(α )

5Elba, 28.05.2006, Roman Schnabel

Amplitude Squeezing at 0

)ˆ(aℜ

)ˆ(aℑ

€

δˆ a 1 =1

2δˆ a (ω + Ω0) + δ ˆ a †(ω − Ω0)[ ]

δ ˆ a 2 =−i

2δˆ a (ω + Ω0) −δ ˆ a †(ω − Ω0)[ ]

Quantum noise

Quantum noiseImproved signal to noise ratio

6Elba, 28.05.2006, Roman Schnabel

Standard design of a squeezed field source, (Optical parametric amplifier,

resonator with MgO:LiNbO3-medium)

Length,

LO,

Generation of Squeezed Fields

Pump field, cw, 532nm

Squeezed field,Squeezed field,cw, 1064nmcw, 1064nm

Crystall

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Optical Parametric Amplification

Generation of phase squeezed light (g1/2=2)

)ˆ(aℜ

)ˆ(aℑ

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Optical Parametric Amplification

Generation of amplitude squeezed light (by deamplification, g1/2=1/2)

)ˆ(aℜ

)ˆ(aℑ

9Elba, 28.05.2006, Roman Schnabel

“Squeezing” and Signal-Recycling

Power-Recycling mirror

Laser

Photo diode

Signal-recycling mirror

Faraday rotator

SHG

OPA

GEO 600 topology

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“Squeezing” and Signal-Recycling

Vacuum (a)

Squeezed vacuum + signal (b)

Signals (c)

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Generation of Squeezed Fields

Technical laser noise

Shot noise

Detector dark noise

Squeezed noise

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Control of Squeezed Vacuum Fields

Carrier Light is Carrier Light is not allowed !not allowed !

13Elba, 28.05.2006, Roman Schnabel

P-pol for OPO length control

Frequency shifted field that still senses

parametric amplification

Control of Squeezed Vacuum Fields

General concept:

Use coherent but not interfering control fields:

Frequency shifted fields

Carrier Light is Carrier Light is not allowed !not allowed !

First audio-band squeezing: [McKenzie et al., PRL 93, 161105 (2004)] New experiment !

14Elba, 28.05.2006, Roman Schnabel

Was wir vorhaben:

15Elba, 28.05.2006, Roman Schnabel

Squeezing in the GW Detection Band

4 dB squeezing

(a) Shot noise, 88W (c) Shot noise, double laser power

(b) Squeezed noise (d) Shot noise, half laser power

[Vahlbruch et al., submitted (2006), available as LSC reviewed manuscript]

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Squeezing in the GW Detection Band

[Vahlbruch et al., submitted (2006), available as LSC reviewed manuscript]

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18Elba, 28.05.2006, Roman Schnabel

Squeezing in the GW Detection Band

(a) Shot noise

(b) Squeezed noise

19Elba, 28.05.2006, Roman Schnabel

Summary

Squeezed field injection is fully compatible with detuned signal recycling and a possible control scheme has been demonstrated (in the MHz regime).

A control scheme for squeezed vacuum fields has been demonstrated which enabled the observation of squeezing from 10 Hz to 10 kHz.