Post on 17-Dec-2015
LINEAR ATOM GUIDE: BUILDING AN ATOM LASER AND OTHER EXPERIMENTSMallory Traxler
April 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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OBSERVED PHENOMENA Penning ionization Remote field ionization
InitialDelayed
Thermal ionization (Radiative decay) Microwave ionization Field ionization
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OBSERVED PHENOMENA Penning ionization Remote field ionization
InitialDelayed
Thermal ionization (Radiative decay) Microwave ionization Field ionization
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OBSERVED PHENOMENA Penning ionization Remote field ionization
InitialDelayed
Thermal ionization (Radiative decay) Microwave ionization Field ionization
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OBSERVED PHENOMENA Penning ionization Remote field ionization
Initialdelayed
Thermal ionization (Radiative decay) Microwave ionization Field ionization
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OBSERVED PHENOMENA Penning ionization Remote field ionization
InitialDelayed
Thermal ionization (Radiative decay) Microwave ionization Field ionization
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OBSERVED PHENOMENA Penning ionization Remote field ionization
InitialDelayed
Thermal ionization (Radiative decay) Microwave ionization Field ionization
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OBSERVED PHENOMENA Penning ionization Remote field ionization
InitialDelayed
Thermal ionization (Radiative decay) Microwave ionization Field ionization
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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