Thesis Defense - Mehmet Öncü (MSEE)

Mehmet Öncü – M.Sc. Electrical & Electronics Engineering

Assist. Prof. Kadir Durak – Advisor

Date: 05.07.2022

Time: 15.30

Location: AB1 412

“Design and Construction of the Fundamental Tools for Single-Atom Experiments”

Assist. Prof. Kadir Durak, Özyeğin University

Prof. Özgür E. Müstecaplıoğlu, Koç University

Prof. H. Fatih Uğurdağ, Özyeğin University

Abstract:

Neutral atoms are one of the most promising systems for quantum information and quantum engineering, in general. Full and efficient control over cold atoms and their interactions with light has been challenging and exciting task, especially for quantum information and engineering. These systems now can be integrated successfully into the applications like the implementation of a quantum internet, simulation and experiments involving nonlinear single photons.

Rubidium atoms provide a playground for atomic physics experiments and applications since it has accessible atomic transition and a readily available two-level system. In order to manipulate single 87Rb atoms, experimental tools should be meticulously prepared. Since the atomic quantum states are delicate and fragile, their interaction with light should be handled with care. For the manipulation of these atoms, low linewidth stable laser systems should be constructed to provide an efficient and effective solution. To achieve the required stability, the external-cavity diode laser (ECDL) and frequency modulation (FM) spectroscopy setups are constructed to obtain the low-linewidth, high-stability laser source.

Alongside the laser setup, an ultra-high vacuum (UHV) setup is constructed and up to a 2.5 ×10−10 mbarvacuumlevelis obtained. To reach ultra-high vacuum levels, additional baking is performed and Rbatomsourceismountedtobereadilyused.UHVsetupisrequiredtominimize the background collisions and decrease the environmental disturbances from the targeted atomic system.

Lastly, optical cavities that will be used to manipulate single atoms are studied in this thesis. Although the strong focusing cavities are used to achieve high coupling strength, they come with several disadvantages. Since they are on the edge of the stability diagram, higher-order mode excitation is dominant for the cases where focusing strength is the highest.  Therefore, knowing the mode structure is important for those regimes to have a complete understanding of these devices. Together with laser and UHV setups, optical cavities are the complementary part of most single-atom experiments.

Bio:

Mehmet O¨ ncu¨ is a member of Dr.  Durak’s Quantum Optics Laboratory (QOptics) team since 2020. He received his bachelor’s degree from the Physics Department at Bilkent University in 2020. He started his master’ program with Dr. Durak in the same year. From the start of his master’ program, he has been working on the project named Increasing Single Atom-Single Photon Interaction for Quantum Computing Applications funded by the Scientific and Technological Research Council of Turkey (Tu¨bitak) with the project number 119F200.  His research interest is in quantum optics and atomic physics in a broad terms. His master’s thesis focuses on the design and construction of the fundamental tools for atomic physics experiments.