The fast pace of technological development in many scientific fields, such as time measurement, single particle detection, temperature or pressure sensing, requires increasingly sensitive sensors. Amongst the different types of metrological devices, optical sensors are particularly interesting due to their versatility and high sensitivity.
Most optical sensors work by coupling the physical quantity of interest to a change in the phase or amplitude of a laser beam, that can be subsequently detected using interferometric techniques. Typical interferometers are able to detect phase changes of the order of a fraction of the optical wavelength. Their sensitivity can be further improved using optical resonators, which can enhance the phase sensitivity by orders of magnitude. Amongst the most promising resonator geometries are the family of Whispering Gallery Mode (WGM) resonators.
WGMs are a family of eigen-modes supported by monolithic circular resonators. These modes are confined inside the cavity through total internal reflection, potentially leading to very high Q factors. Q factors as high as 10^10 have been reported in the literature. Moreover WGM resonators enable much higher power densities than the Gaussian modes carried by more traditional free space systems. WGM based mechanical sensors have been developed to measure forces and pressure as well as temperature and magnetic fields.
This project will focus on the development and characterization of a magnetometer based on WGM. An optical resonator will be combined with a magnetostrictive material such as Terfenol-D that will enable ultra-precision sensing of magnetic fields using fully optical techniques.
- Dr. Jiri Janousek CECS, ANU
- A/Prof. Warwick Bowen, Physics, University of Queensland