Development of a dual-channel scanning microwave/optical microprobe

摘要

A dual-channel scanning microprobe (dual probe) has been developed for simultaneous mapping of microwave and optical properties of a sample. It employs a tunable open-ended coaxial resonator with a tapered and metal-coated fiber optic tip, from which microwave and light can be emitted/collected simultaneously. The microwave channel of this probe, operating at 1.5 GHz, can detect changes in sheet resistance (R_(x)) above 293 mΩ with a spatial resolution ranging from 5 to 10 μm. The optical channel, on the other hand, has a spatial resolution ～1 μm. The poorer spatial resolution in the microwave channel was attributed to its lower sensitivity. Imaging of dielectric grid and high-T_(c) superconducting microwave resonators was carried out at ambient temperature.