2023 Departmental Poster Competition

Silicon nitride photonic chips have emerged as a promising platform for a variety of applications, ranging from communication to sensing. However, their integration with other physical systems, such as microfluidics and atomic vapor cells, remains challenging due to the modal size difference between photonics and these domains. Here, we address this issue by optimizing subwavelength grating metalens for on-chip Gaussian beam generation. We focus on in-plane beam generation, which allows easier integration and alignment with other systems. Our approach involves engineering the modal beam size by arranging metamaterial subwavelength gratings, transforming modal sizes from hundreds of micrometers to a few micrometers. The device is designed on a simple monolithic scheme, which can be readily fabricated by well-established complementary metal-oxide-semiconductor (CMOS) processes. Our device is readily integrable with photonic chips and has the potential to advance various chip-scale photonic applications, including biochemical sensing and atomic wavelength referencing.