Qing Liu successfully defended his PhD on Freeform-based optofluidic devices towards Surface-Enhanced Raman spectroscopy (SERS). It was the first-ever fully online public PhD defence at B-PHOT. Because of the measures taken against the further spread of COVID-19, Qing couldn't hold his defence at the university. However, he managed to give a very nice public presentation during an online session!
Dr. Qing Liu:
"Science is complicated, but we can make it simple and funny. I am very glad everyone enjoyed my presentation, and I have received many positive feedbacks after my defence. Especially for the "Hulk & Hamburger" analogy for explaining Raman spectroscopy."
Material identification is of great importance in industrial production, scientific research and daily life of human beings. Optical detection technologies, among all physical and chemical methods, have become indispensable tools to qualitatively and quantitatively characterize the composition, concentration and properties of the sample under test by analyzing the light interaction with matter. In my PhD, we have developed an optofluidic sensing platform that combines optics with microfluidics lab-on-chip for conventional Raman and SERS analyses in the food-related domains. We have miniaturized the Raman system into an optofluidic lab-on-chip device by using a freeform reflector and integrating a miniaturized confocal Raman probe. Also, we have presented a conical beam shaper in combination with a high NA freeform segmented reflector for obstruction elimination during SERS measurements. In addition, we proposed a 3D printing approach based on two-photon polymerization for fast and flexible SERS substrate fabrication after in-depth FDTD simulation. Due to this realization, we paved the way for tunable, robust, mass-manufacturable and low-cost freeform-based optofluidic Raman and SERS analyses.