Optical magnetic field probe working up to 15 GHz using CdTe electrooptic Crystals

This paper presents a new type of optical magnetic field probe designed to detect magnetic near-fields with high accuracy up to 15 GHz. The probe head consists of a loop antenna element and CdTe electrooptic crystals. The probe using CdTe has a resonant frequency higher than that of a previous probe using LiNbO₃ because CdTe has a dielectric constant lower than that of LiNbO₃. Through an optical technique, a probe doubly loaded with CdTe can work as a conventional double-loaded loop probe without metallic cables or an electrical hybrid junction. We examined probe characteristics up to 20 GHz. We confirmed that the probe could measure magnetic fields near a microstrip line with high accuracy in the gigahertz range.