Terahertz superconducting hot electron bolometer heterodyne array receivers for NASA's GUSTO balloon observatory

Abstract

The electromagnetic spectrum between 1 and 6 Terahertz contains unique information to understand important astrophysical phenomena such as the lifecycle of the interstellar medium (ISM). The latter is the material floating in between stars. The ISM lifecycle is crucial in studying the process of planet, star and galaxy’s formation, and can be traced by the radiation of fine structure lines using heterodyne receivers, a type of spectrometers that combine a high sensitivity with a high spectral resolution, operated from stratospheric balloons or space. GUSTO, the first balloon mission within NASA’s explorer program, is a THz observatory expected to launch in 2023 and will map fine structure lines of nitrogen [NII], carbon [CII], and oxygen [OI] along the Milky Way. This PhD thesis describes the development of the three 8-pixel detector arrays and the multi-beam local oscil-lator (LO) at 4.7 THz for GUSTO. Two chapters address the optimization of the optical beams of the detectors to obtain both uniform and parallel beams within an array. One chapter introduces the array architecture and discusses the performance characterization of the three arrays, demonstrating the highest pixel count monolithic detector array at THz with state of the art performance. The thesis ends with the design of the 4.7 THz LO, which is used to operate the respective array. This PhD research results in not only the key technologies that will be flown on NASA’s GUSTO, but also a scalable solution for the next generation of heterodyne detector arrays