טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentKaminski Samuel
SubjectRipplon Laser
DepartmentDepartment of Mechanical Engineering
Supervisor Professor Tal Carmon
Full Thesis textFull thesis text - English Version


Abstract



This thesis deals with a new approach in the field of optical circuits. The creation of optical integrated circuits with high quality-factor resonators, has been challenging for the past decades. The optical circuits have a great advantage on the electronic circuits since they can give an increasingly amount of bandwidth especially for the use of high speed communication.

The thesis consists 2 parts:

In the first part we show a first step in the creation of an optical circuit. Our new approach is based on the use of optical tweezers for the manipulation of the resonator which is coupled with light. The optical tweezers which are very economical in the terms of space and money, give us the ability to easily control and couple the resonator to a tapered fiber. This ability can even be scalable and enable us coupling of more than one resonator at a time. Another advantage of the optical tweezers is that they enable us to tune the resonators frequency by deforming its shape. In this work we experimentally demonstrate trapping a microdroplet by using optical tweezers and then activating it as a microresonator by bringing it close to a tapered-fiber coupler. Our tweezers facilitated the tuning of the coupling from the under-coupled to the critically-coupled regime while the quality-factor [Q] is 12 million and the resonator’s size is at the 80 µm scale. In the last decade, a lot of research was done in order to create optical circuits at >107 Qs. Our tweezers-controlled resonators constitutes the first step in integrating high-Q cavities.


In the second part we experimentally demonstrate the capillary waves effects in micro-cavities. In early days it was known that gravity affect the mechanical frequencies of ripples. Yet, at the beginning of the 20th century, Lord Rayleigh discovered that as the ripples scale decreases to below a millimeter, surface tension dominates over gravity. In our research we show that capillary oscillations can intermediate stimulated emission of light. This mechanism is second only to the “Phonon Laser” that was introduced by Townes; yet in phonon-lasers, stimulated emission of radiation was intermediate by sound and not by capillaries as is the case here. Using the tweezers-controlled resonators (that we developed in the first part) we succeed to stimulate capillary scattering and to coherently excite capillary modes. The phenomenon is observed by fabricating our special type of liquid-walled microcavity which is made out of octane that has a very-low viscosity. This cavity does not only contain an optical mode but also a capillary one. Therefore the optocapillary cavity enables a resonantly-enhanced energy exchange between light and ripples. Unlike acoustical waves that can propagate in all phases of matter, capillaries represent a striking manifestation of intermolecular forces that is unique to the liquid phase. Our light-mater interaction where stimulated radiation is mediated by ripples might open a new field of study, named optocapillaries.