Supplementary material: Chip-scale atomic spectrometer with silicon nitride optical phased array

The supplementary material includes detailed fabrication steps for the Si3N4 on SiO3 platform, schematics of the spectroscopy and waveguide characterization setups with component breakdowns, descriptions of the three MMI designs, details of the test structure used for MMI characterization, SEM images of the gratings, and additional data on beam displacement, beam divergence, and power broadening measurements.