SystemesSystemes de Reference de Reference TempsTemps——EspaceEspaceObservatoireObservatoire de Paris de Paris
I. I. DuttaDutta, D. , D. SavoieSavoie, M. , M. MeunierMeunier, B. Fang, R. Geiger, C. , B. Fang, R. Geiger, C. GarridoGarrido AlzarAlzar, , A. A. LandraginLandragin
I.Interferometry to Cold Atom Gyroscope
II.Experimental Set-up and Measurements
III.Results and Further Improvements
IV.Remarks
LayoutLayout
http://museumvictoria.com.au/scidiscovery/image_pages/mn004211.asp?URL=/scidiscovery/li
ght/interfere.asp
Principles
of
Interferometry
Atomic interferometer
lasers
atoms
Principles
of
Interferometry
-15-10 -5 0 5 100,0
0,5
1,0
Δφ
Δφ: difference of accumulated phase shift along the two arms : 2 waves interferences
http://greatmindsofscience.tumblr.com/post/217384980
86/the-power-of-observation-part-1
http://museumvictoria.com.au/scidiscovery/image_pages/mn004211.asp?URL=/scidiscovery/li
ght/interfere.asp
Light interferometer
mirror
mirror
beam splitter
light
«
Quantum
»
regime:Cold Atoms
Wave-particle
duality
of
atoms
Transition in internal
states
Gyroscope using
Interferometry
Sagnac
Effect
Experiment
is
rotating
Reference
is
fixed
Sagnac
phase shift :
Atomic Atomic GyroscopeGyroscope
cos121P
E : energy of atomsA : physical area
Manipulating
atomic
wave
packets with light pulses
Bigger
sensitivity
6S1/2 9,2 GHz
6P3/2
852 nm
Raman transitions
D2
line for Cs
A two photon transitionF=3
F=4
Transition between 2 momentum states
7 mm/s
Atom Interferometer MechanismsAtom Interferometer Mechanisms
/2 /2
T T3 Pulse Interferometer
6S1/2 9,2 GHz
6P3/2
852 nm
Raman transitions
D2
line for Cs
A two photon transitionF=3
F=4
Transition between 2 momentum states
7 mm/s
Atom Interferometer MechanismsAtom Interferometer Mechanisms
/2/2
T/2 T T/2
4 Pulse Interferometer
Bigger
Area
Gauguet et al., Phys. Rev. Lett.
97, 010402
(2006)
Inertial Navigation Precision MeasurementsApplications in Geodesy
and Seismology
Applications
Gravity Probe B
SYRTE Gyroscope (Paris)
Aim:Extremely
Precise
and
Stable
Experimental Set Up @ SYRTEExperimental Set Up @ SYRTE
3D MOT
2D MOT
Detection
4 Pulse Geometry: 11cm2 area (max.)30 times
bigger
area than
existing
atom
gyros
Large baseline
but human-size
Cold Atomic
Source (1.4μK) with
fast
repeatability
π/2 Pulse
π
Pulse
2T =800ms possible
Present
day:
2T = 480ms; Area = 2.4 cm2
2 m
InterferometricInterferometric PerfomancesPerfomances
Reduced
Fringe
visibility
:
Vibration Noise
2T = 480ms; Area = 2.4 cm2
Vibration Signal
Inte
rfer
omet
erSi
gnal
EffectEffect ofof Vibration NoiseVibration Noise
Estimation of
Vibration at
the
centre
Commercial Vibration Sensors
Signal Correlation
of
Interferometer
and
External
Sensor
Looking
at
Longterm
Stability
GryoscopicGryoscopic ResultsResults andand TowardsTowards ImprovementsImprovements
Noise + Signal
Extracted
Signal
~15 times
Acquire
Vibration
Noise
Recompensate
in laser for light pulsing
End
Cycle
Start
Cycle
Real
Time
Noise Removal
=Real
Time
Rotation Signal
No post
analysis:More Automation
2.6 parts per billion of 1 rad/s in 2000 s
Ωearth
=73 parts per
millionof
1 rad/s
Best precision
Best stability
0.12 parts per million of 1 rad/s
in 1 s
Result
after
Post
Treatment
of
Data
Method
similar
to “Hybridization”
Lautier
& Lours
et al.Appl. Phys. Lett.
105, 144102
(2014)
Way to Improve:No Dead Time
Short term Limitation:
Under-sampled Parasitic
Vibration Noise
Testing
as a Fountain
Clock
Classical Trajectory
4 Pulse 2 Pulse
Ω
T T
H1
H2
Inertial Noise in Gyro=
Local Oscillator Noise in Fountain Clock
No-Dead-Time: No loss of
Information
Useful for Inertial
Navigation
We lose information
Waiting
to Prepare
Ramsey Pulse
Detection
Height
Time
Dead Time
Φ1(0)
Φ1(T)
Φ2(0)
Φ2(T)
Φ3(0)
Φ3(T)
Φ2(0)
Φ2(T)
Φ3(0)
Φ3(T)Φ1(T)
Φ2(0)
∆Φ1
= Φ1
(T) -
Φ1
(0) ∆Φ2
= Φ2
(T) –
Φ2
(0) ∆Φ3
= Φ3
(T) –
Φ3
(0)∆Φ2
= Φ2
(T) –
Φ2
(0) ∆Φ3
= Φ3
(T) –
Φ3
(0)
Fundamental Noise Limit
With Added Phase Noise
With Added Noise andNo Dead Time
~10 times
Average faster to Fundamental Noise
Cycle Time
TRamsey
= 480 ms
Meunier and
Dutta
et al.Phys. Rev. A
90, 063633 (2014)
Type of Gyro
Research Group/ Industry
Area
Long term
stability (rad/s)
Integration time
Atomic
SYRTE Gryo
(Old
Set Up) (2009)[1]
20 mm2 1×10-8 ~15 mins
SYRTE Gyro (New Set Up)
(2014)2.4 cm2 2.6×10-9 ~30 mins
[1] Gauguet
et al., PHYSICAL REVIEW A 80, 063604 (2009)[2] LEFEVRE, IXBLUE, Comptes
Rendus
Physique (2014)[3] Schreiber et al.,IOPScience, Quantum Electronics, (2014)
< 10-8 rad/s in 1 sec 11cm2 < 10-10 ~30 mins
Optical
Fiber
Optic
Gyro
(IXBLUE) (FR) (2014)
[2]
3 km Long Fiber in loops
5×10-11 38 days
Ring Laser Gyro
(DE) (2014) [3]
16 m2 6×10-13 2 hours
- Seismology
-
Tidal forces-
Variation ofEarth’s rotation
-
Realtivistic
effects
10-9
10-10
10-11
10-12
10-13
10-14
10-15
∆Ω(rad/s)
Effects:
Type of Gyro
Research Group/ Industry
Area
Long term
stability (rad/s)
Integrati on time
Atomic
SYRTE Gryo
(Old
Set Up) (2009)[1]
20 mm2 1×10-8 ~15 mins
SYRTE Gyro (New Set Up)
(2014)2.4 cm2 2.6×10-9 ~30
mins
[1] Gauguet
et al., PHYSICAL REVIEW A 80, 063604 (2009)[2] LEFEVRE, IXBLUE, Comptes
Rendus
Physique (2014)[3] Schreiber et al.,IOPScience, Quantum Electronics, (2014)
< 10-8 rad/s in 1 sec 11cm2 < 10-10 ~30
mins
- Seismology
-
Tidal forces-
Variation ofEarth’s rotation
-
Realtivistic
effects
10-9
10-10
10-11
10-12
10-13
10-14
10-15
∆Ω(rad/s)
Effects:
Large Area Atom Gyroscope:Extremely Precise and Stable
Larger Area+
No-Dead-Time Mode+
Real Time Rotation Signal
End Remarks
Future prospects: Improvement
methods for ourGyroscope
Towards a Standard with bigger area:
11 cm2
area (2T = 800 ms)
Large Area Atomic Gyroscope Scheme
Funding Partners:
Team:Atom Interferometers and Inertial Sensors
DenisSavoie Arnaud
Landragin
BessFang
CarlosGarridoAlzar
RemiGeiger
MatthieuMeunier
Funding Partners:
Team:Atom Interferometers and Inertial Sensors
DenisSavoie Arnaud
Landragin
BessFang
CarlosGarridoAlzar
RemiGeiger
MatthieuMeunier