Elastic Interferometers as Phononic Filters for Thermal Isolation in Low-Noise Transition Edge Sensors

TL;DR

This paper introduces elastic interferometers as a novel phononic filtering approach to achieve high thermal isolation in low-noise Transition Edge Sensors, improving their sensitivity by reducing thermal noise.

Contribution

It presents a detailed elastic wave model of interferometric phononic legs and demonstrates the successful fabrication of TESs utilizing these structures for thermal isolation.

Findings

Elastic wave model of phononic legs developed

Successful fabrication of interferometer-based TESs

Achieved high thermal isolation in TESs

Abstract

In order to achieve low Noise-Equivalent-Powers (NEP < 1 aW Hz$^{-1/2}$) Transition Edge Sensors (TES) require high levels of thermal isolation between the superconducting bilayer and the heat bath. We propose that short micro-machined acoustic interferometers can be used for low-noise thermal isolation, avoiding many of the difficulties inherent in conventional, long- legged TES designs. In this paper, we present a detailed elastic wave model of interferometric phononic legs, and demonstrate the successful fabrication of TESs that are thermally isolated by interferometric structures.