Date

5-6-2024

Document Type

Thesis

Abstract

This thesis is a culmination of our efforts to construct a robust and flexible opto-mechanical system to fully deliver and control all of the parameters related to the required laser wavelength, polarization, power, beam size, and directionality for both the pump and the re-pump laser beams, delivered from two different lasers, necessary for neutral-atom laser trapping and cooling. This is an extension of the neutral Rubidium Magneto-Optical Trap (MOT) at BSU which afford a macroscopic scale collection of cold atoms where the effective governing laws of physics are quantum in nature rather than classical. My predecessors had done work on this system using a single laser with side-band capability and a custom vacuum chamber. My approach uses the commercially available ColdQuanta miniMOT which comes equipped with an ultra high vacuum chamber, Rubidium pump, and a Helmholtz coil all controllable through a single interface. Instead of a singular laser with side-bands we have opted to use a two laser system where we have used Toptica’s DL Pro, due to its very high stability, as our main pump laser to excite the Rubidium atoms and then Toptica’s DL-100 laser to provide a broader spectrum re-pump light to keep atoms from falling into the dark-state, a lower energy state that electrons occasionally fall into after emitting a photon. Our primary pump laser is fiber coupled to Toptica’s Doppler Free Saturated Absorption Spectroscopy COSY which is connected to the DLC Pro laser controller software that allows us to see the scan over a span of frequencies from the laser an find the Rubidium resonance peaks. Then both of our lasers are fiber coupled into a HighFinesse Wavemeter with picometer level resolution so that the wavelengths of the light from both lasers can be observed and altered as needed. This new optical and mechanical design offers a more robust light delivery system with a greater degree of control than previous iterations. Challenges for this research have been numerous from both a mechanical and optical perspective. One of our major concerns has been if the software controlled laser lock is stable enough to achieve a MOT. The Rubidium MOT program supplements both BSU’s Physics and the Photonics and Optical Engineering Program which offers undergraduates research experience and leads to new generations of advanced lab experiments that coincides and compliments new initiatives in both departments for Quantum Technology and Quantum Information Sciences by providing examples and directions using cold atom qubits for quantum computing and simulations. With the improvements made to past students’ efforts and a redesign to the optical pumping system we now find ourselves in a position where achieving a stable MOT is likely due to our complete control over the system’s power, direction, and polarization. We have made great efforts to understand the underlying physics including the quantum numbers associated with the angular momentum of our Rubidium atoms and the energy levels that correspond to them.

Department

Physics, Photonics and Optical Engineering

Thesis Comittee

Dr. Edward Deveney, Thesis Advisor
Dr. Elif Demirbas, Committee Member
Dr. Samuel F. Serna O., Committee Member

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