Department of Physics, Koç University, İstanbul
15 December 2016, Thursday, 14:40
Cavid Erginsoy Seminar Room, Physics Department, 3rd floor
Abstract: Fluids possess unique properties for designing optical components and systems: (i) they have optically smooth interfaces and (ii) they provide a great flexibility in shape and refractive index. Optofluidics has recently emerged as an exciting new research field employing these unique properties of fluids to design optical components and systems that cannot be realized with classical solid-state materials. Optofluidic platforms usually exploit established design and manufacturing principles developed within the past two decades for the production of microfluidic chips. In this presentation, I will present some alternative approaches we have followed in my research group which can serve as inspirations for future optofluidic platforms. Microdroplets of water and other polar liquids take almost spherical shapes when standing on a superhydrophobic surface. With their truncated microsphere geometry, they act as optical microcavities hosting whispering gallery modes. I will summarize the novel spectral tuning techniques, and organic/bio emitting device concepts, we developed using microdroplets that are standing on a superhydrophobic surface or trapped using different manipulation methods. I will discuss the experiments we have performed on optical spectroscopy of microdroplets using tapered optical fibers. I will also discuss our results on hydrogen gas, humidity and ethanol sensing using other optical microresonators such as microsidks or microcylinders. We are also pursuing for obtaining liquid-core optofluidic waveguides based on total internal reflection of light in fluidic channels. For this purpose, we use liquid channels that are either embedded in hydrophobic silica aerogel or obtained after selective wetting of hydrophilic lines produced by laser ablation on a superhydrophobic surface. The results that I will describe were partially supported by TÜBİTAK Grants No: 105T500, 109T734, 110T803, 111T059, 112T972, and 115F446.
Reminder: Tea and cookies will be in the seminar room before the seminar.