Atom Quantum Sensors on ground and in space

Ernst M. RaselAG Wolfgang Ertmer – Quantum Sensors Division

Institut für QuantenoptikLeibniz Universität Hannover

IQ -

Qua

ntum

Sen

sors

Quantum Matter

InertialQuantum Probes

OpticalClocks

IQ -

Qua

ntum

Sen

sors

Quantum Matter

InertialQuantum Probes

OpticalClocks

free falling proof masses

… guiding the satellite

(laboratory system)

Read out of

distance or relative motion by

optical means,

capacitive measurements, or

magnetometersIner

tial s

ensi

ng

Using atoms as microscopicperfect test masses

Iner

tial s

ensi

ng

Using atoms as microscopicperfect test masses

Quantum Test

Absolute Measurement of inertial forces at low frequency

Ideal identical test bodies: atoms

No charging, no aging effect

Sensitivty increases with T2

Col

d 87

Rb Sagnac Interferometer

Interferometer

MOT 1

π/2

ππ/2

15 cm3 mm

A

PreparationDetection

MOT 2

C. Jentsch, T. Müller, E. Rasel, and W. Ertmer, Gen. Rel. Grav, 36, 2197 (2004)& Adv. At. Mol. Physics

sensitive to both types of inertial forces, rotations and accelerations

transportable

3D-MOTmoving molasses

2D-MOTatomic source 2 detection

interferometer

preparation

Source 1Source 2

Col

d A

tom

Sag

nac

Inte

rfero

met

er

Dua

l int

erfe

rom

etry

time

Detuning of the Raman lasers [Hz]

Exc

itatio

npr

obab

ility

Exc

itatio

npr

obab

ility

Exc

itatio

npr

obab

ility

Exc

itatio

npr

obab

ility

Exc

itatio

npr

obab

ility

C1 = 24% C2 = 22%T = 1ms, τ = 7,5µs

π/2π

π/2

Gyr

osco

pe

⋅=∆ Am2 Atomrot

r

hϕ Ω

r

Rotational Sensitivity with 10 8 ats:

Ground 10-9 rad/√Hz @ Expansion Time 0.025 s

Space 8⋅10-12 rad/√Hz @ Expansion Time 3 s

Earth rotation rate:7.2 10-5 rad/s

Acc

eler

omet

er ⋅=∆ kTacc

r2ϕ ar

Accelerational Sensitivity with10 8 ats:

Ground 10-10 g/√Hz @ Expansion Time 0.2 s

Space 10-12 g/√Hz @ Expansion Time 3 s

IQ -

Qua

ntum

Sen

sors

Quantum Matter

InertialQuantum Probes

OpticalClocks

Clo

ck T

echn

ique

s

OscillatorAtomic

Reference

Feedback

Interrogation

Clock work

Narrow Transitions1mHz - 100 Hz

@ 1010-1015Hz

Atom-optical Techniques & Lasers

forCooling & Trapping,

Preparation, Detection

Frequency-stable, compact, reliable

LasersMonolithic solid state &

Fibre lasers

Cavities and Optics

Mechanical Design, Miniaturisation &

Fibres

Clo

ck T

echn

ique

s

OscillatorAtomic

Reference

Feedback

Interrogation

Clock work

Narrow Transitions1mHz - 100 Hz

@ 1010-1015Hz

Atom-optical Techniques & Lasers

forCooling & Trapping,

Preparation, Detection

Frequency-stable, compact, reliable

LasersMonolithic solid state &

Fibre lasers

Cavities and Optics

Mechanical Design, Miniaturisation &

Fibres

Why

Mg

?Narrow to ultra-narrow transition

"Magic" wave length dipole trap (1S0→3P0: 465 nm)

Higher order effects ?

Reasonable abundance of fermionic and bosonicisotopes 24,25,26Mg

Low black-body shift (10-16)

Simple electronic structure- easy to model

Semi-conductor laser + Frequency Doubling

Clock laser: dye laser (200 Hz) → diode laser

Fast and efficient laser cooling

Mg-

optic

alcl

ock-

an u

p da

te Cooling schemes beyond the Doppler limit

2-photon cooling (500 µK 1D, theore. limit 50 µK)

Sisyphus-cooling of the metastable state

First frequency measurement in Mg 1S0→3P1 with a fibre comb generator and a transportable clock of PTB: preliminary value

655.660.083.836 kHz (acc < 10-11)

New set-up delivering more than 109 trapped atoms (loading of about 4*108 at/s)

1stM

g-fre

quen

cy

mea

sure

men

t 655.660.083.836 kHz +/- 3 kHz

Uncertainty ≤ 10-11

Stability: thermal beam 9*10-13 [1s]

cold atoms 8*10-14 [1s] -200000-20000

-10000

0

10000

Ram

sey-

Bor

dé-S

igna

l [a.

u.]

frequency [Hz]

σ(τ=1s)=8,9*10-13

0 1 2 3 4 5 6 7 8 93836

3837

3838

3839 tue.

ν (c

lock

lase

r)-6

55,6

6008

TH

z [k

Hz]

measurement no.

thu.

Err

or B

udge

t

Effect Shift (Hz) Uncertainty (Hz) Rel. Uncertainty(x10-12)

1st order Doppler 0 554

500

150

5

0.1

0.1

761,2

0,845

2nd order Doppler -1643 0,763

2nd order Zeeman 0.84 0,229

Black body radiation -0.19 0,00763

DC Stark shift 0.1 0,00015

Sagnac effect 1.2 0,00015

Total -1641,1 1,161

IQ -

Qua

ntum

Sen

sors

Quantum Matter

InertialQuantum Probes

OpticalClocks

Dropping BEC

Impl

emen

tatio

nFree Fall: up to 9 sec

Duration > 1 BEC-Experiment

3 flights per day

Test of a robust BEC FacilitiesDimensions < 0.6 ∅ x 1.5 m< 234 kg

Height 110 m

QU

AN

TUS

pumps

µ-metal shielding

Battery pack

Laser

DC-DC transformer

Computer control

The QUANTUS Team, Bose-Einstein condensates in microgravity, AppliedPhysics B: Lasers and Optics, http://dx.doi.org/10.1007/s00340-006-2359-y

286 cm

ATK

AT

4 successfull drops of a magneto-optical trap

Generating BEC

• External MOT

• Chip-MOT

• Moving MOT

• Molasses

• Opt. Pumping

• IP-Trap /Dimple trap

• Evaporation

Incr

easi

ngph

ase

spac

eD

ensi

ty

IQ -

Qua

ntum

Sen

sors

Quantum Matter

InertialQuantum Probes

OpticalClocks

Applications

Adv

anta

ges

of µ

-gra

vity

Extended Time of EvolutionSensitivity ~T2

Perturbation-free EvolutionIdeal inertial reference system

No need to compensate gravity /to levitate the atoms

Comparison of different species

EXTENDED PARAMETER RANGE

• Inertial standards/references

• Earth Observation

• Measurement of relativistic effects & gravity

• Pioneer anomaly

• Testing the Weak Equivalence Principle

• Drag-free sensorsperhaps in gravitational wave detectors ?

Fields of Interest:

Ato

mic

Qua

ntum

Sen

sors

Per

spec

tives

Dual Atomic Accelerometer

2 atomic species of 108 atoms < 1µK

combined with a drag free proof mass(Pathfinder or ONERA type / optical read out)

HYPER orbitAccelerational Sensitivity with 10 8 ats:

Space 10-12 g/√Hz @ Expansion Time 3 s

Pat

hfin

der

Nee

dfo

rFem

to-g

With cold atoms ?

Scaling factor

averaging

Averaging √T/τ

Atomic Temperature an issue and beam splitter velocity : T2

The

BE

C-µ

g Te

am

DLR 50 WM 0346

Drop Tower & SpaceIntegration

Robust & Compact Laser

Atomic Quantum Sensors

Atom-Chip

Theory

Techn. support

Kai BongsWiebke BrinkmannHansjörg DittusWolfgang ErtmerTheodor HänschThorben KönemannClaus LämmerzahlWojciech LewozkoRonald MairoseGerrit NandiAchim PetersPeter PrengelErnst M. RaselJakob ReichelWolfgang SchleichMalte SchmidtTilo SchuldtKlaus SengstockThilo SteinmetzChristian StenzelAnika VogelReinhold WalserTim van Zoest

Thank youfor your attention !

ENOUGH SPACE FOR EXCITING EXPERIMENTS