Transcript High-B - University of Michigan
Modification to Various Projects in Raithel’s Lab Louise Niu, University of Michigan REU 2008 Advisor: Georg Raithel http://cold-atoms.physics.lsa.umich.edu Outline 2 Magneto-Optical Trap • Laser Cooling & MOT • Building Compensating Magnetic Coils Bose-Einstein Condensation • How to make a BEC • Building High Voltage Power Supply Laser Cooling 3 Rb Atoms absorb photons in the laser beam Conservation of Momentum Atom slows down Atom spits photons in a random direction Continuous photon stream from one direction One dimensional laser cooling Animation Atom Magneto-Optical Trap (MOT) 4 3 orthogonal pairs of counterpropagating laser beams. Quadruple magnetic field trap atoms in the center. Cool Rb Atoms to 1mK. (MOT) Building Compensating Magnetic Coils 5 Motivation: Create bias magnetic field to adjust MOT postion for Cryo-MOT Design & Setup: 3-dimentional Anti-Helmholtz magnetic field Each pair coils generates 2 gauss magnetic field in its center Vertical direction: wrap coils on the chamber Horizontal plane: coil form+cardboard Made by Louise !! lol Building Compensating Magnetic Coils 6 MATLAB Simulation: Building Compensating Magnetic Coils 7 1. Coil Wrapping 2. Mount Coils 3.Connect to Power Supply Testing 8 Building Compensating Magnetic Coils 9 10 Bose-Einstein Condensation (BEC) Bosonic Atoms: having integer spin Low temperature: very close to absolute zero (10s of nK) Atoms are in the same lowest energy level Atoms are absolutely identical Act as one giant wave 11 How to make a BEC 1. Laser cooling and trapping 2. Turn laser light off and turn 3-D magnetic trap on 11 3. Evaporative cooling: 12 Building High Voltage Power Supply Motivation: To supply high voltage for MCP Micro-Channel Plate: A component to detect Ions Phosphor screen Ions Phosphor screen 13 Building High Voltage Power Supply Power supply High V-source Current meter Power switch Aluminum Box Power plug Building High Voltage Power Supply 14 15 In addition… Other projects: Laser Amplifier Pulsed Coil Atom Laser Software Applied: MATLAB Mathematica Photoshop Adobe Illustrator AutoCAD 16 Acknowledgements Prof. Georg Raithel Graduate Students: Aaron Reinhard Brenton Knuffman Eric Paradis Kelly Younge Mallory Traxler Melinda Morang Rachel Sapiro Rahul Mhaskar Rui Zhang Undergraduate Students: Jordan Montgomery Varun Vaidya Thanks for your attention !