Title: Whispering Gallery Mode (WGM) microresonators for sensing applications

Abstract:

The term whispering gallery mode (WGM) was first introduced to describe the curvilinear propagation of sound waves under a cathedral dome. The physical concept has now been generalised to include light waves continuously reflected along the closed concave surface of an optical cavity, such as a glass microsphere. The circular path of the internally reflected light results in constructive interference and optical resonance, a morphology-dependent resonance suitable for interferometric sensing. WGM resonators are miniature micro-interferometers that use the multiple-cavity passes of light for very sensitive measurements at the microscale and nanoscale, including single-molecule and ion measurements. The presentation includes the techniques used by spherical and fibre-based WGM microresonators for various physical parameter sensing applications such as temperature, strain, bulk refractive index, gas concentration, and presence of magnetic field etc.

Brief Bio:

Dr Kavungl completed his PhD from Technological University Dublin, Ireland, in 2019. Since April 2022, he has worked as a postdoc in Light-Matter interaction for Quantum Technologies Unit (LMI-QT) at OIST. During his PhD, his research was mainly about optical fiber-based whispering gallery mode (WGM) microresonators for sensing applications. The main aim of the research was to investigate and address several key aspects related to developing novel sensors and tunable devices based on cylindrical WGM micro-resonators to move such structures closer to practical applications. In OIST, Dr Kavungal is involved in the research and development towards commercial WGM microresonator-based sensors.