In recent years Microwave Kinetic Inductance Detectors (MKIDs) have emerged as one of the most promising novel low temperature detector technologies. Their unrivaled scalability makes them very attractive for many modern applications and scientific instruments. In this paper we intend to give an overview of how and where MKIDs are currently being used or are suggested to be used in the future. MKID based projects are ongoing or proposed for observational astronomy, particle physics, material science and THz imaging, and the goal of this review is to provide an easily usable and thorough list of possible starting points for more in-depth literature research on the many areas profiting from kinetic inductance detectors.

In this work, the authors investigated MoO3 films with thickness between 30 nm and 1 μm grown at room temperature by solid phase deposition on polycrystalline Cu substrates. Atomic force microscopy, scanning electron microscopy, and scanning tunneling microscopy revealed the presence of a homogenous MoO3 film with a “grainlike” morphology, while Raman spectroscopy showed an amorphous character of the film. Nanoindentation measurements evidenced a coating hardness and stiffness comparable with the copper substrate ones, while Auger electron spectroscopy, x-ray absorption spectroscopy, and secondary electron spectroscopy displayed a pure MoO3 stoichiometry and a work function ΦMoO3 = 6.5 eV, 1.8 eV higher than that of the Cu substrate. MoO3 films of thickness between 30 and 300 nm evidenced a metallic behavior, whereas for higher thickness, the resistance–temperature curves showed a semiconducting character.

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Microwave Kinetic Inductance Detector (MKID) arrays are currently being developed and deployed for astronomical applications in the visible and near infrared and for sub-millimetre astronomy. One of the main challenges of MKIDs is that large arrays would exhibit a pixel yield, defined as the percentage of individually distinguishable pixels to the total number of pixels, of 75 − 80 %. 1 Imperfections arising during the fabrication can induce an uncontrolled shift in the resonance frequency of individual resonators which end up resonating at the same frequency of a different resonator. This makes a number of pixels indistinguishable and therefore unusable for imaging. This paper proposes an approach to individually re-tune the colliding resonators in order to remove the degeneracy and increase the number of MKIDs with unique resonant frequencies. The frequency re-tuning is achieved through a DC bias of the resonator since the kinetic inductance of a superconducting thin film is current dependent and its dependence is non linear. Even though this approach has been already proposed, 2 our innovative pixel design may solve two issues previously described in literature such as non-negligible electromagnetic losses to the DC bias line, and the multiplexibility of multiple resonators on a single feed-line.