Atomic strontium based inertial sensor with micron spatial resolution

(1)

Atomic strontium based inertial

sensor

with micron spatial resolution

G.Ferrarit, A. Alberti,R. E.Drullinger,N.Poli,M.Prevedelli*,M.Schioppo,ESorrentino, G.M. Tino

Dipartimento

diFisicaandLENS, INFN, INFM-CNR,

PoloScientifico-Universita diFirenze, I-50019 Sesto Fiorentino,Italy

(*) also

Dipartimento

di ChimicaFisica, UniversitadiBologna, ViadelRisorgimento 4, I-40136Bologna, Italy

e-mail:

ferrari@lens.unifi.it

Alkali-earth atoms have an electronic level structure particularly suited for applications in matter-wave interferom-etryandhigh-precision laser spectroscopy. Recently atomic strontium was the subject of active research in several

1 2

fields suchas

all-optical cooling

towards

quantum

degeneracy

and detection of

ultra-narrow

optical

transitions .

Because of its small elastic

cross-section3,

we show that ultra-cold

88Sr

in presence of a lattice potential is also particularly well suited for the realization of inertial sensors to accurately measure forces with micro-metric spatial resolution. By loading the sample into a vertical lattice potential we observe persistent Bloch oscillations with a

damping time longerthan 10 seconds4, and from the measured Blochfrequencywe determine the local gravity

with asensitivity of 5 x

10-6g.

Ourresult has directimplicationsinforce measurements at small distances from surfaces such as tests ofpossible deviations form the Newtoniangravity potentialatsub-millimetre distances. Wewill present the status of a force measurement at distances below 20,um from dielectric and metallic surfaces,

which based onultra-cold atomsundergoingBloch oscillations.

Wewill also report on the progress towards the realization of anoptical frequency standard based on thehighly

forbidden

1So-3Po

88Sr intercombination line at 698 nm as well as the realization of a laser suited forprecision

spectroscopy onthis transition.

1H. Katori,T.Ido,YIsoya,andM.Kuwata-Gonokami,PRL82,1116(1999)

2M.Takamoto,F.-L.Hong, R.Higashi,H.Katori,Nature435,321(2005)

3G.Ferrari,R. E.Drullinger,N.Poli,F.Sorrentino,G. M.Tino,PRA73,023408(2006)