Infectious diseases have been posing an omnipresent threat to the global and public health. In order to minimize the spreading of diseases, it is crucial to develop an early detection of pathogenic agents for clinical point-of-care.

In this thesis, we propose and develop the idea of using dye-doped polymer-coated silicon oxynitride microresonator lasers for on-chip active sensing. The use of silicon photonics leverages the well-developed complementary metal-oxide-semiconductor (CMOS) processes for lower-cost and high-volume production. Especially, the silicon oxynitride platform is suitable for biosensing purposes because of its wide transparent spectral window spanning from the visible wavelengths to the near-infrared wavelengths, and thus allowing flexibility towards various...[ Read more ]

Infectious diseases have been posing an omnipresent threat to the global and public health. In order to minimize the spreading of diseases, it is crucial to develop an early detection of pathogenic agents for clinical point-of-care.

In this thesis, we propose and develop the idea of using dye-doped polymer-coated silicon oxynitride microresonator lasers for on-chip active sensing. The use of silicon photonics leverages the well-developed complementary metal-oxide-semiconductor (CMOS) processes for lower-cost and high-volume production. Especially, the silicon oxynitride platform is suitable for biosensing purposes because of its wide transparent spectral window spanning from the visible wavelengths to the near-infrared wavelengths, and thus allowing flexibility towards various sensing and spectroscopy applications. Meanwhile, passive microresonators in other materials such as silica have been proven for single nanoparticles detection. However, passive microresonators require precision wavelength-tunable lasers and high-resolution detection in order to act as a sensor. By converting a passive microresonator into an active one, we believe that it is possible to eliminate the needs of sophisticated characterization equipment, bringing the on-chip active sensors towards to point-of-care applications.

We have designed, fabricated and characterized a myriad of silicon oxynitride microresonators, such as microdisk structures, “Baumkuchen cake” structures, “moat” structures, “TaiChi waveguide” structures and “plum pudding” structures. The passive microresonators are then coated on top with a thin dye-doped polymer film to convert them into active light-emitting microresonators and microlasers. We have demonstrated lasing from the structures using uniform optical pulsed pumping from the top. We have characterized the laser characteristics in terms of the laser threshold, the slope efficiency and the free spectral range of the lasing modes. In terms of the sensing purpose, we have obtained preliminary data on some devices by using a tapered optical fiber tip as a perturbation to mimic a nanoparticle depositing onto the microlaser surface.