The cosmic microwave background is an image of the Universe in its infancy. It spans the entire sky, but it is only visible to detectors that are sensitive to microwaves. Understanding this background with ever-greater precision led to our current understanding of cosmology. Further advances require more sensitive and precise detectors. Johnson and collaborators are developing a novel, potentially transformative technology called Microwave Kinetic Inductance Detectors (MKIDs). Such devices have a superconducting film that is especially sensitive to light. The devices are also sensitive to polarization, which enables them to make further scientific discoveries. MKIDs can be scaled to large arrays, which are needed for precise observations. Johnson and collaborators will create MKIDs using a new material -- manganese doped aluminum. They will build an improved prototype detector with more than ten times the number of pixels and demonstrate its sensitivity and scalability.
This project will develop kilo-pixel arrays of polarization-sensitive Microwave Kinetic Inductance Detectors (MKIDs) that are sensitive to submillimeter radiation in the range 130-280 GHz. MKIDs operate by using superconducting resonators whose resonant frequency changes when incident photons break Cooper pairs in the device. Changes in resonance are monitored by a probe tone that drives the resonator. Each detector can have a unique resonance, which enables multiplexing many pixels onto a single output signal. Such multiplexing may enable very large arrays of detectors. Johnson and collaborators will develop a new MKID design using manganese doped aluminum, which has been used successfully in another detector technology. They will scale up their existing 23 element design to a 331 element module. They will test this prototype and demonstrate that multiplexing factors of ~1000 are achievable. Finally, they will expand the fabrication pipeline to enable production of more devices. This project will demonstrate the performance of these MKIDs to be comparable to competing technology and demonstrate its potential to advance beyond current technology, especially in terms of scalability for large arrays.
