Faculty of Engineering and Natural Sciences
Applications in Micro and Nano-Photonics using Liquid Microdroplets and Single Dye Molecule Tracing
In this talk I will summarize the current research projects we are pursuing at Koç University Nano-Optics Research Laboratory. The projects are divided to two main sub-categories: optical spectroscopy of liquid microdroplets and single dye molecule tracing.
Microdroplets of water and other hydrophilic liquids take almost spherical shapes when standing on a superhydrophobic surface. With their specific truncated microsphere geometry, these microdroplets can provide a three dimensional confinement for light. Provided a large contact angle, the whispering gallery modes of these optical microcavities can possess high quality factors. Besides, no additional position stabilization technique such as optical levitation, electrodynamic levitation, or optical tweezing is necessary to analyze the optical properties of these microdroplets. I will summarize the novel spectral tuning techniques, and organic emitting device concepts we developed using this system. I will also discuss the current experiments we are performing in order to characterize the high quality factors of the whispering gallery modes.
Single molecules are sensitive reporters that can provide detailed information on their host matrices. In our studies, we trace the images of single terrylene molecules embedded in Polybutadiene (PB) – Polyethylene Oxide (PEO) block-copolymer thin films which reveal cylindrical nano-channels filled with PB. Single molecule traces matching the thin film morphology are often observed in our experiments. In some of the traces, single molecules are also observed to switch between parallel cylindrical channels. Mean square displacement curves sometimes show a parabolic dependence to the lag time, suggesting directed diffusion within the channels. This is attributed to the variations in the channel diameters in those cases.
April 10, 2009, 10:40, FENS L048