טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentAttar Sarah-Tehila
SubjectMode Mapping in a Micro-Droplet Resonator
DepartmentDepartment of Mechanical Engineering
Supervisor Professor Tal Carmon
Full Thesis textFull thesis text - English Version


Abstract

Brightness observed on the surface of drops of dew or the colors of a rainbow are examples of common light effects in droplets. These phenomena are based on the way light penetrates a drop and is reflected on its boundaries, until it escapes. Under special conditions, it is possible to trap light within a drop. The drop then acts as an optical resonator and has remarkable optical properties.

In the past few decades, a lot of research has been done in order to build optical circuits on an industrial scale. But beyond the development of the science in this field, the remaining problems are the mass-production of perfectly similar optical resonators, and their integration into optical circuits. In addition, unlike cascadable transistors, coupling optical resonators one to another is challenging. Optical resonators made of liquid, despite the fact that they are less stable than the solid ones, are tunable and hence cascadable. They present many advantages, and can be a new approach to explore.

The purpose of this work is to fabricate and study liquid optical resonators. More specifically, we want to study the light distribution inside a droplet while the cavity is optically resonating. Here, we experimentally map the droplet's optical modes (whispering-gallery modes) using a fluorescent mode-mapping technique. We observe modes as well as crossing between them (level-crossing).

Previous works revealed that an optical resonator can be used for detecting nanoparticles. A nanoparticle, when simply deposited on a solid resonator, disturbs the modes travelling inside it, and can split a mode to two degenerated modes which counter-propagate. Actually, the fact that a nanoparticle can penetrate inside the liquid resonator, and the existence of many level-crossing events, leads us to expect a greater split of a level-crossed mode into two. Thereby, we believe that our liquid resonator can be a more sensitive differential sensor of nanoparticles.