Development of aluminum LEKIDs for balloon-borne far-infrared spectroscopy (Conference Presentation)

Abstract

We are developing lumped-element kinetic inductance detectors (LEKIDs) designed to achieve background-limited sensitivity for far-infrared (FIR) spectroscopy on a stratospheric balloon. The Spectroscopic Terahertz Airborne Receiver for Far-InfraRed Exploration (STARFIRE) will study the evolution of dusty galaxies with observations of the [CII] 158 micron and other atomic fine-structure transitions at z = 0.5 - 1.5, both through direct observations of individual luminous infrared galaxies, and in blind surveys using the technique of line intensity mapping. The spectrometer requires large format arrays of dual-polarization-sensitive detectors with NEPs of 1e-17 W/sqrt(Hz). We pattern the LEKIDs in 20-nm aluminum film, and use an array of profiled feedhorns to couple optical radiation onto the meandered inductors. A backshort etched from the backside to a buried oxide layer insures high absorption efficiency without additional matching layers. Initial testing on small sub-arrays has demonstrated a high device yield and median NEP of 4e-18 W/sqrt(Hz). We describe the development and characterization of kilo-pixel arrays using a combination of dark noise measurements and optical response with our cryogenic blackbody.