Development of metamaterials components for Cosmic Microwave Background experiments.

The properties of natural materials are determined by how the atoms respond to electric and magnetic fields. However, in principle it is possible to create artificial materials building periodic three-dimensional structures where the sub-wavelength unit elements are designed to respond strongly to the electromagnetic radiation. These ’metamaterials’ can be made by using planar metallic grids deposited on dielectric substrates stacked together to form three-dimensional structures. The Astronomy Instrumentation Group (AIG) is world-leading in the design and production of metamaterial devices based on the ‘mesh-filters’. This technology, developed by the academics of this group, has led to the invention of many novel quasi-optical devices that, just a few years ago, would not be dreamt possible. Very accurate modelling combined with the manufacturing skills and expertise of the people working in our cleanrooms allow us to push further this field by designing new and more exotic devices. In this project we propose to develop one of the following quasi-optical devices working at millimetre and sub-millimetre wavelengths:
a) Very large bandwidth mesh half-wave plates (artificial birefringent materials)
b) Large diameter mesh-lenses (flat and thin surfaces providing inhomogeneous phase-delays)
c) Devices able to manipulate the Orbital Angular Momentum (OAM) of light
d) Devices able to perform ‘hardware’ mathematical operations such as spatial differentiation, integration or convolution across the profile of an incoming beam
e) Horn antennas based on metamaterials
f) Artificial Magnetic surfaces

The modelling will be carried out by using electromagnetic finite-element analysis software (Ansys HFSS). The devices will be manufactured within the group facilities and then tested using Fourier Transform Spectrometers (FTSs) and Vector Network Analysers (VNAs).
The majority of this development is targeted to millimetre and sub-mm astronomy instrumentation, in particular that related to the detection of the Cosmic Microwave Background (CMB) B-Modes. The AIG in involved in many CMB projects worldwide as well as in future space mission studies, such as the Japanese LiteBIRD. In addition, this work finds application in telecommunications, radar and security systems.
The PhD research project will consist of:
- Metamaterials electromagnetic modelling using finite-element analysis software (HFSS)
- Design of a novel quasi-optical device
- Assistance in the manufacture of the device within the group facilities
- Testing of the device with FTSs and VNAs
- Analysis and interpretation of the data

This project will start on 01/10/2018