QUANTUM MEMORY FOR STORAGE, BELL STATE MEASUREMENTS… · QUANTUM MEMORY FOR STORAGE, BELL STATE MEASUREMENTS, AND TELEPORTATION SELIM SHAHRIAR, NWU VISITOR: • Dr. Philip Hemmer

QUANTUM MEMORY FOR STORAGE, BELL STATE MEASUREMENTS, AND TELEPORTATION

SELIM SHAHRIAR, NWU

VISITOR: • Dr. Philip Hemmer

• Dr. Venkatesh Gopal• Dr. Gaur Pati• Dr. George Cardoso• Dr. Prabhakar Pradhan

POST-DOCS: • Ken Salit• Jacob Morzinski• Alex Heifetz• Joseph Vornhem

GRAD STUDENTS:

BASIC OBJECTIVES

Demonstrate A Quantum Memory Unit (QMU) In the Form of a Single RbAtom Trapped Inside a High Finesse Cavity

Demonstrate Transfer of Photon Entanglement to a Pair Of QMU’s.

Demonstrate Quantum Teleportation via Measurement of All the Bell States

FORT Beam

Cavity FieldRb Atom

FORT Beam

Cavity FieldRb Atom

THE BASIC MACHINERY

F'

F

5S1/ 2

5P3/2

780.1 nm

3036

29.363.4

120.7

1 2

3

TSL1

VALVE

VALVEO

VEN

SECTIO

N: H

V

MAIN CHAMBER: UHV

FOUNTAIN LAUNCH BEAM: TSL1

S-DL

HP-D

L

UPPER CHAMBER: UHV

TSL3

FOCUSED GUIDE BEAM: TSL3

THE CAVITY AND THE FOUNTAIN

Launch Plus Guide Beams

Pulsed ServoBeam

Pulsed Probe Beam

FORTBeam

Copper Block For Vibration Isolation

THE NEW INTEGRATED CAVITY-FORT: TOP VIEW

FORT beam input port

Piezo

Cavity beamoutput port

Cavity mirrorholder

THE NEW INTEGRATED CAVITY-FORT: DETAILS

OFR FT-51x76

Cavity beam output

FORT beam input

Cavity beaminput

THE NEW INTEGRATED CAVITY-FORT: TWO COPIES

THE FOUNTAIN LAUNCH: NEW AND IMPROVED

AOM 1

AOM 2

AOM 3

To sat. abs.locking

To trap

Launch beam

Timers

on/off

on/off

on/off

Magneticfield

TSL1

LAUNCH BEAM: TSL1

TSL1

~2mmAdjustable

heightDET

IMPROVEMENT: POLARIZATION COOLING TO 100 µK

TRAP EXPANSION WITHOUT PGC

TRAP EXPANSION WITH PGC

THE FOUNTAIN LAUNCH: WITH PGC

LAUNCH BEAM: TSL1

TSL1

~2mmAdjustable

heightDET

THE OLD FORT: IN-SITU

F'

F

5S1/ 2

5P3/2

780.1 nm

3036

29.363.4

120.7

1 2

3

TSL1

TSL3IMAGE INTENSIFIEDCCD CAMERA

DET

FIBER

782.1 nm


TSL1

IMAGE INTENSIFIEDCCD CAMERA

DET

FIBER FORT


TSL1

IMAGE INTENSIFIEDCCD CAMERA

DET

FIBER FORT

THE OLD FORT: IN-SITU∆T=20 m

sec

∆T=10 msec

THE NEW FORT: LAUNCH AND CATCH

TSL1


782.1 nm

LAUNCH

FORT

THE NEW FORT: LAUNCH AND CATCH

LAUNCH CATCH

ATTEMPT AT GUIDED LAUNCH AND CATCH

TSL1


782.1 nm

LAUNCH

FORTGUIDE

ATTEMPT AT GUIDED LAUNCH AND CATCH

LAUNCH WITHOUT GUIDE LAUNCH WITH GUIDE

Precool Atoms Further (e.g., Evaporative Cooling)ALTERNATIVE APPROACHES :

Reduce the Distance Between Cavity and MOT: New ChamberHollow PBG Fiber Plus CO2 Laser Guide For Horizontal Transport

Quadrupolar (Four-Wire) Magnetic Guide and Reduced Distance:Old Chamber Modified

THE ICF: In-Chamber Characterization and Locking

THE ICF: In-Chamber Characterization and Locking

TESTING ATOM-CAVITY COUPLING WITH AN ATOMIC BEAM

CAVITY 1

CAVITY 2UPSIDE-DOWN ATOMIC BEAM

MO

T C

HA

MB

ER

CA

VIT

Y T

RA

NSM

ISSI

ON

LASER DETUNING

CA

VIT

Y T

RA

NSM

ISSI

ON

LASER DETUNING

QUADRUPOLAR MAGNETIC GUIDE, INVERTED CAVITY, REDUCED DISTANCE

FORT

MOT

LAUNCH

QMG

THIS WHOLESTRUCTURE IS IN PLACE IN THEORIGINAL CHAMBER

QUADRUPOLAR MAGNETIC GUIDE: PICTURED BEFORE INSTALLING INSIDE

INVERTED CAVITY, VERY CLOSE TO MOT (NO GUIDE)

FORT

MOT

LAUNCH

THIS WHOLESTRUCTURE IS ALSO IN PLACEIN A NEW CHAMBER

SECOND TRAP CHAMBER WITH THE INVERTED CAVITY, VERY CLOSE TO MOT(NO GUIDE)

BOTH CHAMBERS OPERATING SIDE-BY-SIDE

FORT

MOT

LAUNCH

QMG

FORT

MOT

LAUNCH

QMGFORT

MOT

LAUNCH

FORT

MOT

LAUNCH

MOT

LAUNCH

DEMONSTRATING THE MECHANISM FOR CAPTURING ENTANGLED PHOTON-PAIR AND MEASURING BELL STATES USING AN ATOMIC BEAM

CAPTURING A PAIR OFENTANGLED PHOTONS

MEASURING THE BELL STATES

THE BASIC APPRATUS BASED ON AN EFFUSIVE ATOMIC BEAM

Fluorescence

Imaging lens

Atomic beam

APD

Probe beam circ. pol.0.35 mmhole

Rb

Oven300 oC

1 mmhole

Liquid N2 cooled rod.

Nozzle380 oC Collimator Fluorescence

Imaging lens

Atomic beam

APD


Rb

Oven300 oC

1 mmhole


Nozzle380 oC Collimator Fluorescence

Imaging lens

Atomic beam

APD


Rb

Oven300 oC

1 mmhole


Nozzle380 oC Collimator

Fluorescence

Imaging lens

Atomic beam

APD

Probe beam circ. pol.

0.35 mmhole

Rb

Oven300 oC

1 mmhole



72 MHz

F=2F =3

F =0

F=1

F=15P1/2

5S1/2 F=2

157 MHz

267 MHz

6835 MHz

STEP-ONE: STATE PREPARATION USING PI-POLARIZED OPTICAL PUMPING

F =0

F=1

F=15P1/2

5S1/2 F=2

Fluorescence

Imaging lens

Atomic beam

APD


Rb

Oven300 oC

1 mmhole



72 MHz

F=1

5P1/2

5S1/2 F=2

F =0

F=1

F=15P1/2

5S1/2 F=2

157 MHz

6835 MHz

100 MHz

Lin σ+ +σ-

STEP-TWO: CAPTURING GREEN PHOTON PAIR INTO ZEEMAN COHERENCE

Fluorescence

Imaging lens

Atomic beam

APD


Rb

Oven300 oC

1 mmhole



72 MHz

F=1

5P1/2

5S1/2 F=2

F =0

F=1

F=15P1/2

5S1/2 F=2

157 MHz

6835 MHz

100 MHz

Lin σ+ +σ-

STEP-THREE: EMITTING GREEN PHOTON PAIR FROM ZEEMAN COHERENCE

Sat abs locked on theF=1 F’= 1

AOM + 2x160 MHz

s+, s- Raman zone 2s+, s- Raman zone 3

p zone 1 (opt. Pump),Cir pol zone 4 (probe)

AOM - 2x1610 MHz

AOM - 2x1610 MHz

p Raman zone 2

p Raman zone 3

AOM +100 MHz

p zone 1 (opt. Pump),

Ti-Sapph Laser

GENERATING THE OPTICAL BEAMS FOR ALL THE OPERATIONS

OBSERVATION OF PHASE-LOCKED BLOCH-SIEGERT OSC.

0.35 mmhole

Rb

Oven

1 mmhole~1 mm~1 mm


4.5 mm

7 mm

16.5 mm

RF coil

Nozzle Collimator

~15 cm ~15 cm

Fluorescence

Imaging lens

uB(t)Atomic beam

Opticalpumping

APD

Probe beamRF coil

5P3/2 , F’=0

5S1/2 , F=1∆z1

∆z2

∆z2

∆z2

PUMP

Probe

72.3 MHz

5P3/2 , F’=1

5P3/2 , F’=0

5S1/2 , F=1∆z1

∆z2

∆z2

∆z2

PUMP

Probe

72.3 MHz

5P3/2 , F’=1

5P3/2 , F’=0

5S1/2 , F=1∆z1

∆z2

∆z2

∆z2

PUMP

Probe

72.3 MHz

5P3/2 , F’=1

OBSERVATION OF PHASE-LOCKED BLOCH-SIEGERT OSC.

RF generator Power amplifier Coil, Atomic beam and laser

APD

Low noise pre-amplifiers (~ + 25 dB)

Amplifier

Frequency doubler

SCOPE

ESA

Fluorescence

Channel A

Channel B

DIRECT BSO OBSERVED

BSO

SPEC

TR

UM

OB

SER

VE

D

0.0 1.0 2.0 3.0 4.0

Atom

ic F

luor

esce

nce

(arb

. uni

ts) (b)(a)

0.79T

Time (µs)0 2 4 6 8 10

Atom

ic F

luor

esce

nce

(arb

. uni

ts)

Time (µs)

DIRECT PHASE MEASUREMENT

5P3/2 , F’=0

5S1/2 , F=1∆z1

∆z2

∆z2

∆z2

PUMP

Probe

72.3 MHz

5P3/2 , F’=1

5P3/2 , F’=0

5S1/2 , F=1∆z1

∆z2

∆z2

∆z2

PUMP

Probe

72.3 MHz

5P3/2 , F’=1

5P3/2 , F’=0

5S1/2 , F=1∆z1

∆z2

∆z2

∆z2

PUMP

Probe

72.3 MHz

5P3/2 , F’=1

PROGRESS AND OUTLOOK

Demonstrated launching and catchingDesigned and constructed two integrated cavity-FORT systems

Designed, made, and installed a quadrupolar magnetic guide

Constructed an atomic beam and realized the optical frequencies for testing the Mechanisms behind capturing entangled photons and measuring Bell states. Used this beam to observe a process that can be used for phase teleportation.

Created two separate trap chambers, each with a cavity, and one with a magnetic guide.Cavities in each is close to the MOT, within range of launch and catch

PROGRESS SINCE LAST REVIEW

Established that optical guiding does not work well enough

Catch a single atom in each cavity-FORT systemDemonstrate the entanglement-capturing and Bell-state measuring mechanisms usingthe atomic beam

Attempt generation of distribruted entanglement by capturing a pair of entangled Photons, one in each cavity-FORT system

OUTLOOK BY SUMMER 2004

Demonstrate intracavity teleportation via sequential loading of two atoms in the same cavity , without requiring a source of entangled photons

QUANTUM MEMORY FOR STORAGE, BELL STATE MEASUREMENTS… · QUANTUM MEMORY FOR STORAGE, BELL STATE MEASUREMENTS, AND TELEPORTATION SELIM SHAHRIAR, NWU VISITOR: • Dr. Philip Hemmer

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