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Cavity Resonator for 6.8GHz to hold a Rubidium cell. Itamar Gurman, Yotam Soreq Advisors: Prof. Reuven Shavit (1) , Dr. David Groswasser (2) , M. Givon (2) Department of Electrical and Computer Engineering Department of Physics. Table of contents.
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Cavity Resonator for 6.8GHz to hold a Rubidium cell Itamar Gurman, Yotam Soreq Advisors: Prof. Reuven Shavit(1), Dr. David Groswasser(2), M. Givon(2) Department of Electrical and Computer Engineering Department of Physics
Table of contents • Motivation – atom’s energy levels and Rabi oscillations • Potential usage • Specifications • The Cavity • Conclusions • Further work
Atoms and energy levels • According to quantum mechanics, the atom’s electrons can have quantized energy levels (as opposed to continuous values). • When analyzing the atom’s energy level, we refer only to the electron in the highest level. • Transmission from an energy level to another is achieved by absorbing a photon with an energy equal to the gap between the two levels ΔE=hfphoton.
Rubidium 87 • 87Rb has only one electron in the outer orbit. • Its approximated Hamiltonian:
Rabi oscillations • Once isolated to two energy levels, we can treat it as a 2-state problem. • Creating oscillations between two levels, its frequency dependent on the flux of the photons (intensity of the e.m. wave).
Potential usage • Atomic clock • Magnetometer • Quantum computer
Specifications • Central frequency – 6.8347 [GHz] • Bandwidth – 12[MHz] • Quality factor – 100-600 • Unified magnetic field along Rubidium cell (1 inch) and along the width of the laser beam (5[mm] diameter) • Ability for fine tuning
z d 2a x,y Regular cylindrical cavity • The only modes with a magnetic field along the symmetry axis is TE0mn • The magnetic field – • The electric field along the symmetry axis equals to zero. • Problem – doesn’t provide a unified enough magnetic field.
Metallic shell Cavity’s void 2a d L d Dielectric layers Creating a uniform magnetic field • Solving the problem by adding dielectric layers, changing the boundary conditions. • The new magnetic field:
The Cavity – structure Coax connection Rubidium Cell • Length – 40mm • Radius – 22.44mm • Screw – 1-9mm Copper connection Laser holes Fine tuning screw Dielectric (epsilon=4.22) Aluminum • Holes diameter – 10mm • Each dielectric layer – 6.48mm
The Cavity – magnetic field Cell edges
The Cavity – magnetic field Edge of laser beam
Conclusions • Achieving the prime goal – creating a unified magnetic field along z axis. • Excitation using a coil - impedance matching. • Suitable for varying lengths of cavities. The magnetic field is hardly dependent on the length.
Further work • Allowing the ability to insert a 2MHz field to the cavity (travelling wave). • Manufacturing the cavity. • Measuring S11 and Rabi Oscillations.