Magnetometry and microscopy of cold atom clouds
Ottó Elíasson
This thesis covers experimental work conducted within two distinct fields of cold-atom physics. The first part describes an experiment capable of spatially-selective dispersive measurements of a cold-atomic system in part or in whole, by virtue of a digital micromirror device (DMD). Atom clouds are trapped in optical tweezers made and controlled by an acousto-optical deflector. Two types of high-precision magnetometers are realised. One is vectorial and reaches a single-shot precision of dB = (100, 200) µG for the field components parallel and transversal to the probe light, exceeding a previous realisation by two orders of magnitude. The other is a scalar magnetometer based on Larmor precession and reaches dB = 30 µG, putting it on equal footing with other state-of-the-art cold-atom magnetometers. The second part is devoted to the characterisation and the first results of a new quantum gas microscope experiment. It features a 0.69 NA microscope objective for high-resolution fluorescence imaging of individual atoms trapped in deep optical lattices. The imaging system is shown to perform near the diffraction limit. By means of DMD-generated off-resonant tight optical tweezers, projected through the high-resolution optics, we can load only a few planes of a co-propagating 1D lattice. In a single realisation of the experiment we acquire multiple fluorescence images, where the objective is translated between images, bringing different planes of the optical lattices in focus. In this way we can tomographically reconstruct the atom distribution in 3D.
•Jan 1, 2020•1 citation