Precision Atomic Optics at the IQ - Perspectives in applied & - PowerPoint PPT Presentation

Precision Atomic Optics at the IQ - Perspectives in applied & fundamental sciences AG Wolfgang Ertmer Institut für Quantenoptik, Hannover Leibniz Universität Hannover

II nd generation atom optical experiments Heritage of PHARAO/ACES project dedicated to inertial atomic quantum sensors Lense-Thirring effect Test of the equivalence principle On the horizon: Optical clock works (1999/2000) Lattice clock (2001)

IQ - Quantum Sensors Optical Clocks Inertial Quantum Quantum Probes Matter

From microwaves to Magnesium Opt. Clock optical frequencies ∆ ν 18 − ≈ 10 10 10 Hz → 10 15 Hz ν Mg frequency standard Instability 8·10 -14 Q =2.3*10 12 Sterr et al., Appl. Phys. B 54, 341 (1992) J. Keupp, et al., High-resolution atom interferometry in the optical domain, E.J. Physics D, Highlight Paper (2002) H, Ca, What will be the „best“ atom Mg, Candidates What will be the „best“ clock Sr, Criteria ? Ag, What to be tested ? Yb, Diversity of Clocks Hg, …

Feedback Narrow Atomic Atomic Transition Oscillator 1mHz - 100 Hz Frequency-stable, Reference Clock Techniques compact, reliable @ 10 10 -10 15 Hz Lasers Interrogation Monolithic solid state & Atom-optical Techniques & Lasers Fibre lasers for Cavities and Optics Cooling & Trapping, Mechanical Design, Preparation, Detection Miniaturisation & Clock work Fibres

the Mg frequency 1 S 0 → 3 P 1 655.660.083.836 kHz +/- 3 kHz Precision £ 10 -11 1 st measurement of Evaluation ongoing 2 nd order Doppler shift ~1.5 kHz ~30% bis 42% hin u. rück nicht gut überlappt weniger Leistung ! Do. ~63% Di. weniger 3841 Leistung ! ohne umgepoltes -12 σ ( τ =1)=2,2*10 B-Feld B-Feld 3840 7000 3839 f (blau) in kHz Y Axis Title Signal 3838 0 mit B-Feld 3837 wie immer 3836 -7000 Phasenplatte phi = 0 3835 -180000 -120000 -60000 X Axis Title Frequency 3834 1 2 3 4 5 6 7 8 9 10 11 12 messung

∆ ν 18 − ≈ 10 ν Systematics M. Takamoto et al., Nature, 435, 321 (2005)

U Narrow to ultra-narrow transition "Magic" wave length dipole trap ( 1 S 0 → 3 P 0 : 465 nm) U Higher order effects ? U Reasonable abundance of fermionic and bosonic Mg- optical clock isotopes 24,25,26 Mg U Low black-body shift (10 -16 ) U Simple electronic structure- easy to model Semi-conductor laser + Frequency Doubling U Fast and efficient laser cooling

U Narrow to ultra-narrow transition "Magic" wave length dipole trap ( 1 S 0 → 3 P 0 : 465 nm) U Higher order effects ? U Reasonable abundance of fermionic and bosonic Mg- optical clock isotopes 24,25,26 Mg U Low black-body shift (10 -16 ) U Simple electronic structure- easy to model Semi-conductor laser + Frequency Doubling U Fast and efficient laser cooling

Cooling strategies

C2PC - Coherent 2-Photon Cooling a simple avenue to µicroKelvin • stimulated by W. C. Magno, R. L. Cavasso, and F. C. Cruz, Phys. Rev. A 67, (2003) • Coherent effects of high relevance in magnesium → also observed by N. Malossi et al. , Phys. Rev. A 72, (2005)

3 1 D 2 3 1 D 2 3 1 D 2 2 MHz 2 MHz 2 MHz 881 nm 881 nm 881 nm loss 3 1 P 1 3 1 P 1 3 1 P 1 Verlust Verlust Verlust 80 MHz 80 MHz 3 3 P 1,2 3 3 P 1,2 3 3 P 1,2 285 nm 285 nm 3 1 S 0 3 1 S 0 3 1 S 0 1-D Configuration C2PC ctd. Velocity selective Switch for the photon pressure

3 1 D 2 3 1 D 2 3 1 D 2 2 MHz 2 MHz 2 MHz 881 nm 881 nm 881 nm loss 3 1 P 1 3 1 P 1 3 1 P 1 Verlust Verlust Verlust 80 MHz 80 MHz 3 3 P 1,2 3 3 P 1,2 3 3 P 1,2 285 nm 285 nm 3 1 S 0 3 1 S 0 3 1 S 0 k B T Dopp =D/ α 40000 40000 F/m [m/s 2 ] F/m [m/s 2 ] C2PC ctd. Cooling Cooling 20000 20000 v[m/s] v[m/s] -6 -6 -4 -4 -2 -2 2 2 4 4 6 6 -20000 -20000 Heating Heating -40000 -40000

C2PC - a simple extension of Doppler cooling Accessible temperatures ~200 µK Fast cooling scheme: 1-2 ms C2PC ctd. Technical heating of UV-MOT influences also C2PC Bridges temperature gap for Quench cooling K. Moldenhauer, M. Riedmann, N. Rehbein, J. Friebe, E.M. Rasel and W. Ertmer, IQ, Leibniz Universität Hannover; T.E. Mehlstäubler, SYRTE, Paris " First observation of sub Doppler temperatures in magnesium, in prep. for subm. to PRL

γ 3 ≈ 3 MHz Avenue below µK Ω 2 Γ eff = Γ + 23 Γ 2 3 Quench Cooling –only efficient for cold atoms below the Doppler temperature Laser Cooling in dipole traps operated at magic wavelength N. Rehbein et al., "Quenching metastable magnesium" sub. to Phys. Rev. A T. Binnewies, G. Wilpers, U. Sterr, F. Riehle, J. Helmcke, PTB; T. E. Mehlstäubler, E. M. Rasel, W. Ertmer, IQ, Leibniz Universität Hannover, "Doppler cooling and trapping on forbidden transitions", Phys. Rev. Lett. 87, p. 123002, 2001. T.E. Mehlstäubler, J. Keupp, A. Doulliet, N. Rehbein, E.M.Rasel and W. Ertmer, J.O.B 5, p.183 (2003)

IQ - Quantum Sensors Inertial Quantum Probes Optical Quantum Clocks Matter

Using atoms as microscopic perfect test masses free falling proof masses Inertial sensing … guiding the satellite (laboratory system) Read out of distance or relative motion by � optical means, � capacitive measurements, or � magnetometers

Fields of Interest: Atomic Quantum Sensors • Inertial standards/references • Earth Observation • Measurement of relativistic effects & gravity • Pioneer anomaly • Testing the Weak Equivalence Principle • Drag-free sensors perhaps in gravitational wave detectors ?

The Earth‘s rotation: Ω E ˜ 7,2·10 -5 rad/s GOM SYRTE ∆Ω / E Ω Kasevich Gyro E 10 -0 - earth rotation Rotation sensing 10 -1 10 -8 – 10 -9 rad 10 -2 VLBI 10 -3 in 24 h 10 -4 - seismics our goal (single shot) 10 -5 10 -6 10 -10 – 10 -11 rad/s vHz -1 - tide forces 10 -7 Ringlaser Wettzell 10 -8 - variation of earth rotation 10 -9 rad / 1 year 10 -9 - relativistic effects 10 -10 - galactic rotation 10 -11 Gravity 10 -12 Probe B HYPER

Wettzell Stanford CASI (light) (thermal Cs- (cold Rb-atoms) atoms) length [cm] 400 200 15 area 16m 2 26mm 2 25mm 2 9x10 -11 6x10 -10 2x10 -9 sensitivity [rad.s -1 Hz -1/2 ] Comparison different application for interferometer using atoms: • small device portable sensor Ω • inertial sensitivity in 3 dimensions x , y , z [B. Canuel, F. Leduc, A. Clairon, Ch.Bordé and A. Landragin, Phys.Rev.Lett. 97, 010402 (2006) ]

Rotational induced Phase shift: Sagnac Effect for Light : for Atoms : Gain by de Broglie-Wellen : ∼ 10 11

Sagnac Interferometer Cold 87 Rb Interferometer π π/2 Detection π/2 Preparation 3 mm 15 cm A MOT 2 MOT 1 C. Jentsch, T. Müller, E. Rasel, and W. Ertmer, Gen. Rel. Grav, 36, 2197 (2004) & Adv. At. Mol. Physics

Cold Atom Sagnac Interferometer preparation Source 2 interferometer Source 1 3D-MOT moving molasses detection atomic source 2 2D-MOT

0,30 |e, p at + � k 〉 |e, p at + � k 〉 0,25 0,20 transition probability |g, p at 〉 |g, p at 〉 0,15 Dual interferometer 0,10 r Laser k |g, p at 〉 |g, p at 〉 0,05 L 0,00 -0,05 0 100 200 300 400 pulselength [ µ s] 0,45 C1 C2 0,40 transition probability 0,35 π π /2 0,30 π /2 0,25 C 1 = 24% C 2 = 22% T = 1ms, τ = 7,5 µ s 0,20 0 5 10 15 20 25 30 35 40 phase [rad]

Intense Atomic Sources 9 2,0x10 9 3D-MOT atom number 1,5x10 9 1,0x10 Loading rate into 3D-MOT: 9 5,6*10 At/s 8 5,0x10 0,0 0 500 1000 1500 2000 [ms] T. Müller, T. Wendrich, M. Gilowski, C. Jentsch, E.M.Rasel and W. Ertmer, " "Versatile compact sources for high resolution dual atom interferometry" in prep. for Phys. Rev. A

for degenerate matter Laser light for MOT Laser light for dipole trap Holder for glass cell and 2D- MOT coils and mount for All-optical source telescopes MOT coils Glass cell Rb and K dispensers 50 cm Titanium sublimation pumps Ion pumps C. Klempt, T. van Zoest, T. Henninger, O. Topic, E. Rasel, J. Arlt , W. Ertmer; Phys Rev A 73 , 013410, (2006)

• Extended Time of Evolution Advantages of µ-gravity • Perturbation-free Evolution • No need to compensate gravity / to levitate the atoms EXTENDED PARAMETER RANGE

Quantum IQ - Quantum Sensors Matter Optical Inertial Clocks Quantum Probes

Pilotproject QUANTUS Ultra-cold atoms Inertial Sensors Pilotproject „QUANTUS“ ~ T 2 atom optic components Atomic clocks for space • large, shallow traps • giant de Broglie waves Atom Lasers & • de Broglie resonators Quantum matter • constant de Broglie waves

Free Fall: up to 9 sec Duration > 1 BEC-Experiment 3 flights per day Test of a robust BEC Facilities Implementation Dimensions < 0.6 ∅ x 1.5 m < 234 kg Height 110 m

DC-DC transformer Computer control Laser pumps µ-metal shielding QUANTUS Battery pack 286 cm The QUANTUS Team, Bose-Einstein condensates in microgravity, Applied Physics B: Lasers and Optics, http://dx.doi.org/10.1007/s00340-006-2359-y

molasses T~15 µK ~3·10 6 atoms on the Chip magnetic trap lifetime 2.5 s evaporation works first drops this year interferometry Status mesoscopic trap → talk by A. Peters

Perspectives ?