Research Projects

Photonic integrated circuits (PIC) are crucial for developing devices that translate fundamental research in optics to practical applications in different fields, including communication, computation, quantum information, as well as life sciences. With their inherent stability, scalability, small footprint and tunability, PIC platforms significantly outperform bulk optical systems in carrying out complex tasks with exceptional repeatability and flexibility. Due to its strong demand for telecommunication, PIC technology has been well-established in the infrared (IR) spectrum, and significant developments have already been made in the visible range. However, the potential of PICs for short visible and UV wavelengths, spectrum range which is important for several applications including bioimaging, remains largely unexplored. This project aims to expand PIC technology to this untapped territory by focusing on a novel platform based on thin film lithium niobate (TFLN) and demonstrating its use for super-resolution microscopy (SRM) for bioimaging. SRM is especially important in biosciences as it enables to investigate the structure and organization of cellular matter in biological specimen] and allows for accurate diagnosis, disease progression and better treatment planning. Current PIC-based SRM has demonstrated significantly enhanced field-of-view and resolution, however, it is limited to 405-660 nm spectra due to the restricted transparency range of the constituent materials, hindering the exploitation of the unique property of biological samples in the blue-near UV spectra, e.g. 375-405 nm. The 375-405 nm is a high absorption band for biosamples that leads to highly contrast imaging, enabling label-free imaging. In fact, there is only a very limited choice of materials which are transparent over this range and also allow for waveguide integration. Lithium niobate (LN) is one such exceptional material, which has a wide transparency range (350 nm - 4000 nm), and a high refractive index and simultaneously provide strong electro-optic, piezo-electric and non-linear optical properties. Traditional LN waveguides had lower refractive index contrast and thus larger footprint. TFLN, on the other hand, addresses these issues by utilizing the well-established lithography and etching techniques to pattern nanoscale waveguides with high refractive index contrast enabling tight light confinement. However, it has only been recently that the work on TFLN has gained momentum, and the full potential of this platform remains to be harnessed. In this project, we aim to showcase the potential of the TFLN integrated photonic chip by realising optical elements which are efficient over a wide spectral range and demonstrate bioimaging using them. The main objectives of the proposed research are to develop low-loss and efficient functional elements on TFLN photonic chip with a broad spectral response including 375-405 nm range and to demonstrate TFLN chip-based SRM for label-free bioimaging. The project will be pioneer in harnessing the versatile properties of TFLN to push the boundaries of the current chip-based SRM by enabling the technology to exploit strong absorption properties of biosamples at lower wavelengths and imaging them with enhanced resolution, high contrast and large field of view. Furthermore, we will explore LN electro-optics to develop active photonics circuits for beam shaping that offer enhanced features in imaging. The proposed research is highly multi-disciplinary and benefits from the complementary expertise of the project team. The outcome of the research is multifold and will significantly advance the development of the novel TFLN-based PIC technology, covering different spectrum ranges and also deliver a beyond state-of-the-art TFLN chip-based SRM technique, important for biosciences and diagnostic studies.