Frequency Following Imaging of Electric Fields from Resonant Superconducting Devices using a Scanning Near-Field Microwave Microscope

TL;DR

This paper introduces a cryogenic scanning near-field microwave microscope capable of imaging electric fields in superconducting devices, providing detailed spatial and frequency information at various temperatures and heights.

Contribution

The study presents a novel microwave imaging technique at cryogenic temperatures with a frequency-following circuit to analyze superconducting resonators.

Findings

Microwave images of electric field distribution above a superconducting microstrip resonator.

The use of a frequency-following circuit to study probe influence on resonant frequency.

Imaging performed at different heights and temperatures.

Abstract

We have developed a scanning near-field microwave microscope that operates at cryogenic temperatures. Our system uses an open-ended coaxial probe with a 200 mm inner conductor diameter and operates from 77 to 300 K in the 0.01-20 GHz frequency range. In this paper, we present microwave images of the electric field distribution above a Tl2Ba2CaCu2O8 microstrip resonator at 77 K, measured at several heights. In addition, we describe the use of a frequency-following circuit to study the influence of the probe on the resonant frequency of the device.