Linear Atom guide: building an atom laser and other experiments

LINEAR ATOM GUIDE: BUILDING AN ATOM LASER AND OTHER EXPERIMENTSMallory TraxlerApril 2013

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MOTIVATION Continuous atom laser

Continuous, coherent stream of atomsOutcoupled from a BEC

Applications of atom lasers:Atom interferometry

Electromagnetic fields Gravitational fields

Precision measurement gyroscopesAtom lithography

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OVERVIEW Guide α

Experimental apparatus Experiments in guide α

Rydberg atom guiding Design and manufacture of guide β

Improvements from guide α’s design Outlook

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GUIDE :EXPERIMENTAL APPARATUS

α

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GUIDE OVERVIEWα

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LEVEL DIAGRAM:RB 87

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Φpmot≈3x109 s-1

<vz,pmot>≈22 m/s

2D+ MOT Φmmot≈4.8x108 s-1

2.2 m/s to 2.9 m/s

cos)(

v

PRIMARY & SECONDARYMAGNETO-OPTICAL TRAPS

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OPTICAL DETECTION Detect atoms at the end Uses pulsed probe (23) and probe

repumper (12) Optimize atoms in the guide

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ION IMAGING Three lasers for

excitationRepumper to get back to

bright state5S1/25P3/2 480 nm to 59D

Ionize Voltages on electrode,

guard tube, MCP direct ions upward to MCP for detection

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EXPERIMENTS IN GUIDE :RYDBERG ATOM GUIDING

α

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INTRODUCTION TO RYDBERG ATOMS High n-principal quantum number

Data here with n=59 Physically large

r~n2

Very susceptible to electric fieldsα~n7

Strong interactionsOther Rydberg atomsBlackbody radiation

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EXPERIMENTALTIMING

Excitation to 59D Variable delay time, td MI or FI Camera gated over ionization duration

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OBSERVED PHENOMENA Penning ionization Remote field ionization

InitialDelayed

Thermal ionization (Radiative decay) Microwave ionization Field ionization

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InitialDelayed


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InitialDelayed


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InitialDelayed


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Initialdelayed


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InitialDelayed


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InitialDelayed


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InitialDelayed


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RYDBERG GUIDING DATA Vary td from

5 μs to 5 ms τMI=700 μs

τ59D5/2=150 μs

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FI: INTERNAL STATE EVOLUTION State-selective field

ionizationDifferent electric

field needed for different states

59D peak broadensState mixing

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RYDBERG GUIDING RECAP Rydberg atoms excited from ground

state atoms trapped in guide Observe Rydberg guiding over several

milliseconds using microwave ionization and state selective field ionization

Numerous phenomena from Rydberg atoms within the guide

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GUIDE :DESIGN AND PROGRESS

β

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GUIDE Improvements over guide α

Zeeman slowerNo launchingMagnetic injectionMechanical shutter

β

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1MOT Standard 6-beam MOT Fed by Zeeman slower Factor of 6.6 brighter

Expect closer to 10x

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2MOT CHAMBER Most complicated

part of the design 4 racetrack 2MOT

coils 8 injection coils Built-in water cooling Magnetic

compression Mechanical shutter

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2MOT COILS 4 racetrack coils

produce quadrupole magnetic field

Holes Optical accessVenting of

internal partsShutter

2 locks for stationary shutter

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INJECTION COIL MOUNT 8 injection coils of

varying diameters Fits inside 2MOT coil

package Water cooling for all Tapered inside and

out

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STEEL PIECE, STATIONARY SHUTTER Magnetic compression Mount for waveplate-mirror Stationary shutter

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IN-VACUUM COILS Hand-turned on lathe

2MOT coils on form Injection coils directly

on mount Labeled with UHV

compatible ceramic beads

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INJECTION COILS High current power

supply Split off 2-3 A for each

coil Adiabatically inject atoms

into the guide

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21 equally spaced silicon surfaces

Bring guided atomic flow closer to these surfaces

Atoms not adsorbed onto surface rethermalize at lower temperature

SURFACE ADSORPTION EVAPORATIVE COOLING

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GUIDE RECAP Fully constructed Preliminary tests well on the way Good transfer of atoms into the 2MOT Need Zeeman slower and 2MOT working

simultaneously to optimize

β

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EXPERIMENTAL OUTLOOK

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SHORT TERM OUTLOOK:TRANSVERSE COOLING Increase capture volume of Zeeman

slower Reduce transverse velocity by factor of

x, increase density by factor of x2

Most optics already in place

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LONGER TERM OUTLOOK:POTENTIAL BARRIER Potential barrier at the end of the guide Form BEC upstream Use coil to create potential

Study BEC loading dynamics, number fluctuations

Later use light shield barrierTunnel atoms through to make first

continuous atom laser

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RAITHEL GROUP PI

Prof. Georg Raithel

Former Post Docs Erik Power Rachel Sapiro

Former Grad Students (on this project)

Spencer Olson Rahul Mhaskar Cornelius Hempel

Recent Ph.D. Eric Paradis

Graduate Students Andrew Cadotte Andrew Schwarzkopf David Anderson Kaitlin Moore Nithiwadee Thaicharoen Sarah Anderson Stephanie Miller Yun-Jhih Chen

Current Undergraduate Matt Boguslawski

Former Undergrads Varun Vaidya Steven Moses Karl Lundquist

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PICTURE SUMMARY

Linear Atom guide: building an atom laser and other experiments

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