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New transportable atom sensors and their applications to space - - PowerPoint PPT Presentation
New transportable atom sensors and their applications to space - - PowerPoint PPT Presentation
New transportable atom sensors and their applications to space experiments P . Bouyer Source Atomiques Cohrentes et Interfromtrie Atomique Groupe dOptique Atomique Laboratoire Charles Fabry de lInstitut dOptique Campus
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September 06 Transportable Atom Sensors ... - P. BOUYER 3
Atom accelerometer
Based on Raman pulses atom optics
π/2 − π − π/2 (Kasevich & Chu 1991) : interferometer
π/2 : create a superposition of 2 different velocities : beam splitter π : exchanges velocities : mirror
We use an (optical) ruler to precisely measure the (atomic) test mass position
Similar to falling corner cube gravimeter (FG5)
FG 5 : Laser phase is read by optical interferometry Atom sensor : Laser phase is read by atom interferometry.
An Atom Interferometer “reads” the position of an atom proof mass using some kind of “laser telemetry” Velocity measurement improves with time Acceleration measurement improves with time Absolute accuracy
Example : watt balance for kg definition
Performances Similar to best sensors
Extension to low frequency
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September 06 Transportable Atom Sensors ... - P. BOUYER 3
Atom accelerometer
Based on Raman pulses atom optics
π/2 − π − π/2 (Kasevich & Chu 1991) : interferometer
π/2 : create a superposition of 2 different velocities : beam splitter π : exchanges velocities : mirror
We use an (optical) ruler to precisely measure the (atomic) test mass position
Similar to falling corner cube gravimeter (FG5)
FG 5 : Laser phase is read by optical interferometry Atom sensor : Laser phase is read by atom interferometry.
An Atom Interferometer “reads” the position of an atom proof mass using some kind of “laser telemetry” Velocity measurement improves with time Acceleration measurement improves with time Absolute accuracy
Example : watt balance for kg definition
Performances Similar to best sensors
Extension to low frequency
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September 06 Transportable Atom Sensors ... - P. BOUYER 4
Atom Gyrometer
3 Raman pulses separated in time
Atoms with an initizal velcity perpendicular to lasers
sensitivity to rotation = coriolis acceleration
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Atom Interferomtry : basic principle Atom Inertial Base (gyro + accelerometer) Coherent Atom Sensors I.C.E. : Tranportable Sensor for 0g tests Some possible space applications
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September 06 Transportable Atom Sensors ... - P. BOUYER 6
M axim um interaction tim e : 80 m s 3 rotation axes, 2 acceleration axes C ycling frequency 2H z S ensitivity (10 6 at):
- gyroscope : 3,5 10 -7 rad.s -1.H z -1/2
- accelerom eter : 8 10 -7 m .s -2.H z -1/2
50 cm 30 cm
O ne pair of R am an lasers sw itched on 3 tim es
M agneto-O ptical Traps
D etections
Launching velocity: 2.4 m .s -1 H orizontal velocity: 0.33 m .s -1
Cold Atom Inertial Base (SYRTE)
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September 06 Transportable Atom Sensors ... - P. BOUYER 7
Metrology
Accelerometer precision of a few 10-10 m/s2 per shot (5 s interrogation time) Limit due to Raman-laser phase noise Noise comes from quartz oscillator
It is possible to go to a few seconds of interrogation time
Well suited for space applications Best atom source ? Nyman et al., cond-mat/0605057 and App. Phys. B 84(4) 673
Ultimate limits for atom accelerometers ?
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Atom Interferomtry : basic principle Atom Inertial Base (gyro + accelerometer) Coherent Atom Sensors I.C.E. : Tranportable Sensor for 0g tests Some possible space applications
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September 06 Transportable Atom Sensors ... - P. BOUYER 9
Why Coherent Source
0.01 0.1 1 10 100 1000
Température maximale (µK)
0.01
2 3 4 5 6 7
0.1
2 3 4 5 6 7
1
2 3 4 5 6 7
10
Temps d'interrogation (s)
BEC Sub Doppler
Ultra cold
Longer interrogation Better signal to noise
but lower flux !
Atom Laser : space applications
Small source «New» Physics Correlation, condensed matter Le Coq et al., App. Phys. B 84(4)
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September 06 Transportable Atom Sensors ... - P. BOUYER
Gravitational “resonator” for BEC
10
2 resonance condition B ragg (or R am an) resonance O scillation resonance
See C. Bordé’s Talk Impens, Bouyer, Bordé , App. Phys. B 84(4)
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September 06 Transportable Atom Sensors ... - P. BOUYER 11
BEC : New generation of Interferometers
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September 06 Transportable Atom Sensors ... - P. BOUYER 11
Heisenberg limited with
number states
Compensates low atom number S/
N=106
Integrated interferometers
BEC on chips
«active» interferometers
Matter wave amplification»
BEC : New generation of Interferometers
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September 06 Transportable Atom Sensors ... - P. BOUYER 12
A Guided Atom Laser
So far, RF outcoupled lasers from a magnetic trap
Once atom lasers are extracted, they are subjected to gravity λ becomes quickly very small
- W. Guerin et al., cond-mat/0607438
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September 06 Transportable Atom Sensors ... - P. BOUYER 12
A Guided Atom Laser
- W. Guerin et al., cond-mat/0607438
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September 06 Transportable Atom Sensors ... - P. BOUYER 12
A Guided Atom Laser
BEC in hybrid (magnetic+optical) trap
Focused Nd:YAG laser (red detuned: 1064 nm) Anisotrop: 2,5 Hz × 360 Hz ( zR= 2.7 mm ) Waist position chosen with translational stage
It is possible to use RF outcouplig RF extracted matter wave is guided in the optical trap Large de Broglie wavelength (1 µm)
- W. Guerin et al., cond-mat/0607438
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Atom Interferomtry : basic principle Atom Inertial Base (gyro + accelerometer) Coherent Atom Sensors I.C.E. : Tranportable Sensor for 0g tests Some possible space applications
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September 06 Transportable Atom Sensors ... - P. BOUYER 14
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September 06 Transportable Atom Sensors ... - P. BOUYER 15
ICE : Strategy
Use optical traps for “atom cavity” Optical fields easilly switchable
No stray fields, only “diffusive effects” Precision knowledge on position, velocity …
Compact BEC source :
Crutial : effjcient loading scheme into the
- ptical trap
Need powerfull laser
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September 06 Transportable Atom Sensors ... - P. BOUYER 16
Atomic Physics Chamber
Robust, flexible
Light Source (s)
Doubled telecoms
Control
Real-time
Computing
Man-machine interface
Measurement
Camera, accelerometer
Fibre optics
- I. C. E. : structure
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September 06 Transportable Atom Sensors ... - P. BOUYER 17
Box superstructure Damped (foam filled) Grooves for adding optics anywhere in the volume Breadboard (low vibration) Suspend vacuum chamber with ropes, slings, chains Adjust tension with turnbuckles
- I. C. E. :Cube
87Rb MOT,
10/02/200 6
2×108 at. in <5s
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September 06 Transportable Atom Sensors ... - P. BOUYER 18
- I. C. E. : Cubes (with atoms)
87Rb MOT,
10/02/200 6
2×108 at. in <5s
Box superstructure Damped (foam filled) Grooves for adding optics anywhere in the volume Breadboard (low vibration) Suspend vacuum chamber with ropes, slings, chains Adjust tension with turnbuckles
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Atom Interferomtry : basic principle Atom Inertial Base (gyro + accelerometer) Coherent Atom Sensors I.C.E. : Tranportable Sensor for 0g tests Some possible space applications
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September 06 Transportable Atom Sensors ... - P. BOUYER 20
Atoms sensors in space : missions
General Relativity
Mapping the Lense-Thirring effect around the earth. Equivalence Principle
Testing deviations of the gravitational law at short and long distances.
Pioneer Anomaly Beyond Casimir Effect
Mapping the gravitational potential with absolute gravity gradiometers
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September 06 Transportable Atom Sensors ... - P. BOUYER 20
Atoms sensors in space : missions
General Relativity
Mapping the Lense-Thirring effect around the earth. Equivalence Principle
Testing deviations of the gravitational law at short and long distances.
Pioneer Anomaly Beyond Casimir Effect
Mapping the gravitational potential with absolute gravity gradiometers
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P . Bouyer Source Atomiques Cohérentes et Interférométrie Atomique
Groupe d’Optique Atomique Laboratoire Charles Fabry de l’Institut d’Optique Campus Polytechnique, France
Philippe BOUYER Robert NYMAN Gaël VAROQUAUX Jean-François CLEMENT Jean-Philippe BRANTUT
- F. Impens