introduction to hyper measuring lense-thirring with atom interferometry
DESCRIPTION
Introduction to HYPER Measuring Lense-Thirring with Atom Interferometry. P. BOUYER Laboratoire Charles Fabry de l’Institut d’Optique Orsay, France. Agenda. Introduction to Lense-Thirring Effect Key requirements for the HYPER mission The Payload : Atomic Sagnac Unit - PowerPoint PPT PresentationTRANSCRIPT
Introduction to HYPERMeasuring Lense-Thirring with Atom Interferometry
P. BOUYERLaboratoire Charles Fabry de l’Institut
d’OptiqueOrsay, France
2 ESTEC, March 6th
Agenda
Introduction to Lense-Thirring Effect
Key requirements for the HYPER mission
The Payload : Atomic Sagnac Unit
Atom Inertial sensors : How does-it work ?
HYPER and future space missions
Early earth-based Atom Inertial sensors
Ongoing earth based projects
3 ESTEC, March 6th
The Lense-Thirring Effect
QuickTime™ et undécompresseur Vidéo 1 Microsoftsont requis pour visionner cette image.
General relativistic effect Gravitomagnetism Curvature of space-time
around massive rotating bodies
Courtesy of Astrium
4 ESTEC, March 6th
The Lense-Thirring Effect General relativistic effect
gravitomagnetism Curvature of space-time
around massive rotating bodies
Strong effect near black holes Precession and twist of
acretion disks
QuickTime™ et undécompresseur codec YUV420sont requis pour visionner cette image.
QuickTime™ et undécompresseur Animationsont requis pour visionner cette image.
QuickTime™ et undécompresseur Animationsont requis pour visionner cette image.
Images from Center for Theoretical Astrophysics University of Illinois at Urbana-Champaign
5 ESTEC, March 6th
The Lense-Thirring Effect General relativistic effect
gravitomagnetism Curvature of space-time
around massive rotating bodies
Strong effect near black holes Precession and twist of
acretion disks Small effect close to earth
Possible to measure average frame dragging
– LAGEOS– GP-B
6 ESTEC, March 6th
The Lense-Thirring Effect General relativistic effect
gravitomagnetism Curvature of space-time
around massive rotating bodies
Strong effect near black holes Precession and twist of
acretion disks
Small effect close to earth Possible to measure
average frame dragging– LAGEOS– GP-B
Mapping Lense-Thirring– HYPER
7 ESTEC, March 6th
Agenda
Introduction to Lense-Thirring Effect
Key requirements for the HYPER mission
The Payload : Atomic Sagnac Unit
Atom Inertial sensors : How does-it work ?
HYPER and future space missions
Early earth-based Atom Inertial sensors
Ongoing earth based projects
8 ESTEC, March 6th
The HYPER mission configuration
The Lense-Thirring effect The periodic cycle is
half the orbit period– 2 ASU in
quadrature
Geodetic de Sitter 40 to 80 times bigger Constant for circular
orbit
3x10-14 rad/s
-3x10-14 rad/s
9 ESTEC, March 6th
The HYPER mission configuration
MISSION DRIVERS & CONSTRAINTS Low-Earth Orbit (for mapping the Lense-Thirring effect) Extremely demanding pointing accuracy
Relative Pointing Error: 10-8 radians (2 marcsec) over 3 sec Stable relative pointing between PST and ASU
Drag-free environment 10 -9 g residual accelerations Precise control of gravity gradients
The Lense-Thirring effect Maximum about 10-14 rad/s
– 1 year integration– High accuracy of rotation
measurement
10 ESTEC, March 6th
Agenda
Introduction to Lense-Thirring Effect
Key requirements for the HYPER mission
The Payload : Atomic Sagnac Unit
Atom Inertial sensors : How does-it work ?
HYPER and future space missions
Early earth-based Atom Inertial sensors
Ongoing earth based projects
11 ESTEC, March 6th
ASU1
ASU2Precision Star Tracker Pointing
Cold Atom Source
ASU Reference (connected to the Raman Lasers
& to the Star Tracker)
The HYPER Payload
12 ESTEC, March 6th
ASU1
ASU2
Precision Star Tracker
Raman Lasers Module
Laser Cooling Module
Expected Overall Performance:
3x10-15rad/s over one year of integration i.e. a S/N~10 at twice the orbital frequency
ASU Resolution: 3x10-11rad/s /Hz
Payload components
13 ESTEC, March 6th
Agenda
Introduction to Lense-Thirring Effect
Key requirements for the HYPER mission
The Payload : Atomic Sagnac Unit
Atom Inertial sensors : How does-it work ?
HYPER and future space missions
Early earth-based Atom Inertial sensors
Ongoing earth based projects
14 ESTEC, March 6th
Manipulating atoms with light
Atom Interferometry uses laser induced resonance oscillation
Atoms with 2 different states (red/blue) with different energy
Laser with frequency equal to energy difference
QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.
Time
15 ESTEC, March 6th
Manipulating atoms with light
Controlling the interfaction time controls the result of the oscillation
Half way between red and blue– /2 pulse
Time
16 ESTEC, March 6th
Manipulating atoms with light
Controlling the interfaction time controls the result of the oscillation
Half way between red and blue– /2 pulse
Another half : all the way from red to blue
– pulse
Time
17 ESTEC, March 6th
Manipulating atoms with light
Controlling the interfaction time controls the result of the oscillation
Half way between red and blue– /2 pulse
Another half : all the way from red to blue
– pulse The other way : from blue to red
– pulse
Time
18 ESTEC, March 6th
Manipulating atoms with light
The /2 pulse is a beam splitter Half way between red and blue Coherent superposition of red and
blue
19 ESTEC, March 6th
Manipulating atoms with light
The /2 pulse is a beam splitter Half way between red and blue Coherent superposition of red and
blue
The red and blue states correspond to different kinetic energies
Velocities along laser direction Blue : excited state
– Photon absorbed from laser
– Photon momenum transferred to atom
– Recoil velocity ≈1cm/s
Red : «ground» state– No photon absorbed
– No velocity
QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.
20 ESTEC, March 6th
The Atom Interferometer
The first /2 pulse - beam splitter Creates the coherent
superposition
QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.
21 ESTEC, March 6th
The Atom Interferometer
The first /2 pulse - beam splitter Creates the coherent
superposition
The two parts of the atom separate Splitting between the two parts
QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.
22 ESTEC, March 6th
The Atom Interferometer
The first /2 pulse - beam splitter Creates the coherent
superposition
The two parts of the atom separate Splitting between the two parts
Apply the pulse - mirror Changes blue to red
– Velocity from 0 to recoil
Changes red to blue– Velocity from recoil to 0
QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.
23 ESTEC, March 6th
The Atom Interferometer
The first /2 pulse - beam splitter Creates the coherent
superposition
The two parts of the atom separate Splitting between the two parts
Apply the pulse - mirror Changes blue to red
– Velocity from 0 to recoil
Changes red to blue– Velocity from recoil to 0
Apply last /2 pulse when the two parts overlap again
QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.
24 ESTEC, March 6th
The Atom Interferometer
The first /2 pulse - beam splitter Creates the coherent
superposition
The two parts of the atom separate Splitting between the two parts
Apply the pulse - mirror Changes blue to red
– Velocity from 0 to recoil
Changes red to blue– Velocity from recoil to 0
Apply last /2 pulse when the two parts overlap again
Red or Blue output depend of phase difference between two path
QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.
phase difference
Atomic State
QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.
25 ESTEC, March 6th
The atom «reads» the phase of the laser
Each time the atom changes state, the laser imprints its phase on the atom
QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.
«Stationary» Laser Phase eikx«Stationary» Laser Phase eikx«Stationary» Laser Phase eikx«Stationary» Laser Phase eikx«Stationary» Laser Phase eikx
26 ESTEC, March 6th
The atom «reads» the phase of the laser
Each time the atom changes state, the laser imprints its phase on the atom
00 11
27 ESTEC, March 6th
The atom «reads» the phase of the laser
Each time the atom changes state, the laser imprints its phase on the atom
00 11
QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.
28 ESTEC, March 6th
The atom «reads» the phase of the laser
Each time the atom changes state, the laser imprints its phase on the atom
00 11
2l2l 2r2r
29 ESTEC, March 6th
The atom «reads» the phase of the laser
Each time the atom changes state, the laser imprints its phase on the atom
00 11
2l2l 2r2r
QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.
30 ESTEC, March 6th
The atom «reads» the phase of the laser
Each time the atom changes state, the laser imprints its phase on the atom
00 11
2l2l 2r2r
0033 Final phase differenceFinal phase difference ( (1 1 2r2r2l 2l 33
31 ESTEC, March 6th
QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.
Phase shift comes from acceleration
00 11
2l2l 2r2r
0033 Final phase differenceFinal phase difference ( (1 1 2r2r2l 2l 33
32 ESTEC, March 6th
The atomic sagnac unit
3 separated diffraction zones
Corriolis acceleration comes from rotating laser
QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.⋅=Φ A
hm22 at
rot ΩL
t2
vvL= Ω
33 ESTEC, March 6th
The atomic sagnac unit
3 separated diffraction zones
Corriolis acceleration comes from rotating laser
Rotation and acceleration signal are mixed
Need dual ASU for real rotation measurement
⋅=Φ Ahm22 at
rot ΩL
t2
vvL=
2L
2
vLkacc =Φ 2
driftT ⋅ = ⋅a a
Ω QuickTime™ et undécompresseur Photo - JPEGsont requis pour visionner cette image.
34 ESTEC, March 6th
Interferometer length 60 cm
Atom velocity 20 cm/s
Drift time 3 s
109 atoms/shot
Sensitivity 3x10-11 rad/s
The atomic sagnac unit
35 ESTEC, March 6th
MISSION DRIVERS & CONSTRAINTS Typical measurement time : 3 sec Typical rotation sensitivity of ASU : 10-11 rad/s (1 sec) Signal detection : 2.2x10-15 rad/s rms @ half orbit ASU measures lasers rotations/vibrations
Low-Earth Orbit (for mapping the Lense-Thirring effect) Extremely demanding pointing accuracy
Relative Pointing Error: 10-8 radians (2 marcsec) over 3 sec Stable relative pointing between PST and ASU about 1 arcsec
Drag-free environment 10-9 g residual accelerations Precise control of gravity gradients
– Knowledge and/or control to better than 10-10 g/m
36 ESTEC, March 6th
Agenda
Introduction to Lense-Thirring Effect
Key requirements for the HYPER mission
The Payload : Atomic Sagnac Unit
Atom Inertial sensors : How does-it work ?
HYPER and future space missions
Early earth-based Atom Inertial sensors
Ongoing earth based projects
37 ESTEC, March 6th
HYPER and future space missions
HYPER can benefit from TD of other missions PHARAO/ACES
– Laser Cooling Benches– Radiofrequency chains
LISA/SMART-2/GOCE/MICROSCOPE– Drag Free– Accelerometers
LAGEOS/GOCE/MICROSCOPE– AOCS (low orbit)
GP-B– Precision Star Tracker (HYPER more demanding)– Also from LISA
38 ESTEC, March 6th
Agenda
Introduction to Lense-Thirring Effect
Key requirements for the HYPER mission
The Payload : Atomic Sagnac Unit
Atom Inertial sensors : How does-it work ?
HYPER and future space missions
Early earth-based Atom Inertial sensors
Ongoing earth based projects
39 ESTEC, March 6th
Stanford laboratory gravimeter
10-8 g
Courtesy of S. Chu, Stanford
40 ESTEC, March 6th
Stanford/Yale laboratory gravity gradiometer
1.4 m
Distinguish gravity induced accelerations from those due to platform motion with differential acceleration measurements.
Demonstrated diffential acceleration sensitivity:4x10-9 g/Hz1/2 (2.8x10-9 g/Hz1/2 per accelerometer)
Atoms
Atoms
L a
s e
r B
e a
m
Courtesy of M. Kasevich, Stanford
41 ESTEC, March 6th
Stanford/Yale laboratory gyroscope
AI gyroscope, demonstrated laboratory performance:2x10-6 deg/hr1/2 ARW< 10-4 deg/hr bias stability
Rotation rate (x10-5) rad/sec
-10 -5 0 5 10 15 20
Normalized signal
-1
0
1
Rotation signal
Bias stability
Compact, fieldable (navigation) and dedicated very high-sensitivity (Earth rotation dynamics, tests of GR) geometries possible.
Courtesy of M. Kasevich, Stanford
42 ESTEC, March 6th
Agenda
Introduction to Lense-Thirring Effect
Key requirements for the HYPER mission
The Payload : Atomic Sagnac Unit
Atom Inertial sensors : How does-it work ?
Early earth-based Atom Inertial sensors
HYPER and future space missions
Ongoing earth based projects
43 ESTEC, March 6th
Cold Atom Inertial Base (Paris)Courtesy of A. Landragin (Paris)
Theoretical model (include. relativity) by C. Bordé
44 ESTEC, March 6th
CASI : Cold Atom Sagnac Interferometer (Hannover)
Rubidium-87
launch velocities: 1 m/s
enclosed area A 0.2 cm2
expected sensitivity: Ω 10-8-10-9 rad/sHz-1
Courtesy of E. Rasel (Hannover))
45 ESTEC, March 6th
Courtesy of G. Tino (Fireze)
46 ESTEC, March 6th
Interferometry with Coherent Ensemble (Paris)
QuickTime™ et undécompresseur RVB Plansont requis pour visionner cette image.
ONERA-SYRTE-IOTA-CNES project
Explore Best coherent source configuration for space
Study coherence properties of degenerate source of atoms
Interferometry with coherent sources
Courtesy of P. Bouyer (Paris)