Study of Light Interactions with Magnetic Systems

Supervisor: Dr Rair Macedo

School: Engineering

Description:

Strong light-matter interactions hold the key to new technological developments, such as quantum information processing. In this project, the student will be expected to investigate properties of strong magnon-photon interactions. Here, magnons refer to elementary excitations of spins in ordered magnetic materials such as ferromagnets or antiferromagnets.  These excitations can then couple with photons and generate large resonances within the material -- of the same kind as those in strings on musical instruments. Such hybrid systems (magnon-photon pair) are promising candidates for applications as they can combine the advantages of the different physical systems and overcome the limitations of a single one. While hybrid quantum circuits represent a tool for the deliberate control of quantum states, through said polaritons, light-matter interactions can be thought as an equivalent for macroscopic systems. Thus, the study, understanding, and manipulation of this type of interaction are vital parts of developing spintronic applications.

Magnetic polaritons of this nature are usually excited by millimetre-waves (those operating at GHz and THz frequencies). These waves are widely used in communication and signal processing system. For this purpose, during the last decades we have witnessed incredible progress in high frequency semiconductor electronics. However, despite an increased use of millimetre wave technology there is still a large gap of advances in structures working at high GHz frequencies. A way to circumvent this is by using magnetic materials as these can be used to engineer resonances with greater field tunability.

 

In this project, the student will design and investigate the behaviour of magnetic samples when in contact with oscillating microwave fields and how their properties can be further tuned using externally applied magnetic fields. This will allow for the further study of these samples into electromagnetic devices. Therefore, they learn applied microwave engineering as well as how to simulate and design a transmission line circuit within a magnetic field.  This project would suit students with an aptitude for computer programming and basic knowledge of electromagnetism and/or microwave circuits.