Towards the trapping of single potassium atoms in optical tweezers

Abstract

This thesis presents the development of a toolbox for trapping 39K atoms in a magneto-optical trap with the future vision of trapping a single atom in an optical tweezer. Such technique promise with potential applications in the fields of quantum computation, quantum information, quantum simulation, and precision measurement. In this work, we studied spectroscopic of two different transitions of 39K then we trap 39K in an MOT, which is a small step toward optically trap a single 39K atom in a tweezer.

In the second chapter, we present a summary of the theoretical framework relating to laser cooling and trapping. Also, include a detailed description of the energy level structure and challenges for cooling potassium. In the third chapter, we demonstrated a laser frequency stabilization technique. We include theoretical understanding along with the experimental results. We compare the D1 and D2 transitions of 4S to 4P lines of 39K by various experimental parameters.
In the fourth chapter, we present a history of pre-cooling of alkali atoms is necessary. We also explain our experimental apparatus require required for laser cooling. Then we discuss the laser system used for the experiments along with the alignment technique for the laser beam and AOMs alignment to control the frequencies. We also characterized and set up the tapered amplifer to increase the laser beam power.

And in chapter ve, we present the optimization and characterization of the different experimental parameters of the pyramid MOT to produce as much as bright MOT as possible.

In chapter sixth, we present details of the theoretical framework required to understand the absolute absorption of 4S to 5P transition of 39K along with the experimental results. For the future extension, to study the precision measurements to identify the Rydberg states of cold 39K atoms. And in order to cool down 39K atoms beyond the Doppler cooling limit, one can use degenerate Raman sideband cooling via the 4S1/2 to 5P1/2 transition.

Finally, in the last chapter, we discuss the immediate future experiment in order to achieve a single atom in an optical tweezer. Therefore, after slowing down the atoms in the pyramid chamber as we did for 39K, one can trap 39K atoms in a 3D-MOT in the science chamber, then using optical tweezers with a specific wavelength, one can trap 39K single atom in optical tweezers.