Modelling, development and characterisation of Microwave Kinetic Inductance Detectors for optical astronomy

Abstract

In this thesis I report on the research I carried out on the topic of Microwave Kinetic Inductance Detectors (MKIDs) over the last four years. After an introduction chapter and a literature review on MKIDs, Chapter 3 describes the work carried out during the commissioning of a cryogenic laboratory in DIAS. Here, I introduce the primary equipment that was used, including the cryostat and it’s electronics, alongside some custom-made parts which I designed, such as the sample boxes for the MKIDs. The fourth chapter includes a description of the two pieces of LabVIEW software that I have developed. The first enables the interfacing of a computer with a resistance bridge in order to perform critical temperature measurements. The second is used to control a monochromator that, along with other sources, was used to illuminate the detectors and to perform optical characterisation of ARIEL dichroics. The two subsequent chapters describe the full development process of an MKIDs array, from the design and simulation of an array (Chapter 5) to the cleanroom fabrication process that I developed (Chapter 6). In Chapter 7, I discuss the importance of understanding and simulating the behaviour and performance of MKIDs in terms of fabrication yield and energy resolution. Chapter 8 addresses the issue of improving the fabrication yield; I propose the DC-bias of selected resonators to re-tune their resonant frequency and achieve an overall 12.5% improvement in fabrication yield. I present a feasibility study, published an SPIE proceedings, and suggest a possible design to reach an 87.5% yield. Chapter 9 details the characterisation process and results of two developed MKID arrays. I also describe the first detector which was capable of producing a detectable pulse when illuminated. It was used as a proof of concept and it exhibits moderate resolving power in the order R ∼ 2 − 3 in the optical and near-infrared. I Chapter 10 summarises the main results of the experimental research that I have carried out during this PhD. Chapter 11 presents a literature review on the application of MKIDs outside visible and near-infrared astronomy and discusses where else the work presented in this thesis could be applicable; this study forms the basis of a review paper published by the DIAS MKIDs group. Finally, Chapter 12 presents further work that will be conducted at the Dublin Institute for Advanced Studies alongside possible technological improvements on Microwave Kinetic Inductance Detectors. In the appendices, the reader can find further details on the experimental setup, the derivation of some equations used in the body of the text and some further discussion on the noise performance of the MKIDs. In Appendix A1, the reader can also find a side project I undertook, which is the optical characterisation of the D-3 dichroic for the Ariel telescope.