Despite advances in astronomy, much of the universe remains hidden behind gas and dust clouds that absorb optical radiation, making it undetectable by conventional telescopes. Far-Infrared (FIR) radiation is capable of propagating through these clouds, and offers a solution for observing these obscured interstellar regions. However, the sensitivity of existing detector systems is insufficient to detect FIR radiation effectively. This thesis focuses on the development of highly sensitive detectors based on Microwave Kinetic Inductance Detectors (MKIDs) that meet the sensitivity requirement for use in future space missions, specifically the NASA led POEMM and PRIMA missions, covering a frequency range from approximately 1.5 THz to 12 THz.

While detectors have been developed previously covering the upper band of this frequency range at 6.98 THz and 12 THz, the lower band remains uncovered. Therefore, lens-absorber coupled MKIDs designed to operate at 1.5 THz are presented, with their performance analysed using models based on the Geometrical Optics-Fourier Optics (GOFO) technique in combination with a Floquet wave approach for periodic absorbers. Additionally, the design methodology of MKIDs to operate at specific readout frequencies is discussed. Absorber coupled MKIDs are limited to lower resonance frequencies with respect to comparable antenna based MKIDs, which offer advantages for space-based missions due to reduced power consumption, but do present challenges for readout systems operating at higher frequencies. In this thesis, two lens-absorber coupled MKID designs were developed and are currently being fabricated as candidates to experimentally demonstrate highly sensitive detector arrays operating at 1.5 THz.

The imaging spectrometers in the POEMM and PRIMA missions require a dispersive element to separate different wavelengths of the incoming radiation. The dispersive element envisioned for these missions, the Virtually Imaged Phased Array (VIPA), suffers from non-idealities, causing phase aberrations in the transmitted field, and part of the power transmitting towards unwanted propagation directions, which can degrade instrument performance. This thesis presents and analyses optimisation techniques to mitigate these effects, thereby enhancing the overall efficiency and degrees of freedom for designing the full instrument.

Furthermore, absorbers, unlike antenna-based devices, are multi-mode detectors. Understanding how absorbers couple to higher-order modes is crucial for optimising their performance. This thesis introduces and validates a model based on a novel experimental technique, Energy Absorption Interferometry (EAI), to extract a modal description of detectors. In the future steps related to the POEMM mission, the findings from this initial investigation into multi-mode absorbers will be used to gain insight and explore possible improvement routes in the coupling of these detectors to complex optical systems.

In the ADome project, a truncated icosahedron is used as a frame for multiple antenna nodes. These nodes are used to measure the radiation pattern of an antenna-under-test located in the center of this dome. Since these antennas can be placed anywhere in the ADome by the user, a calibration system is necessary to find the spherical coordinates of each of these antennas.

In this thesis, a method is proposed that uses computer vision algorithms, written using the OpenCV library in C++, to locate each of these antennas by detecting controllable LEDs attached to the PCBs of the antenna nodes. The found pixel locations will then be used to get the spherical coordinates of the antennas with respect to the camera. Finally these spherical coordinates will be transformed to fit to the coordinate system of the ADome itself, by detecting landmarks in the form of fiducial markers which are located at predetermined locations.

The methods of recognition of the antennas within using computer vision are discussed, implemented and tested on real and simulated data. The accuracy of finding the antennas on the real data was within 2 pixels from the true location.

The methods regarding estimating the location of the antenna with respect to the camera are discussed next. These methods include a distortion estimation and correction, after which each pixel will get there corresponding spherical angles θ and φ. These methods are also tested on simulated and real data, where the accuracy on the real data falls within 0.5 degrees in comparison to the true data.

Finally the methods of transforming the spherical angle θ and φ of the antenna with respect to the camera, to the coordinate system of the ADome are discussed. This starts with a method of recognizing fiducial landmarks (landmarks are accurately known reference points), where in this research there is chosen for ArUco fiducials. After this, the location of these landmarks can be used to determine the location and orientation of the camera within the ADome. The method of finding the distances between each of the landmarks and the camera, is discussed and tested and has an accuracy of 2 cm. The method of finding the location of the camera, and the method of finding the orientation of the camera are discussed, however this has not been tested and fully implemented yet. With this location and orientation the location of an antenna can be easily determined.

In conclusion, this thesis is a good starting point for designing an Optical Calibration System, which could make determining the location of each of the antennas faster, and more accurate.