Metal-mesh optical filters are optical filters made from stacks of metal meshes and dielectric. They are used as part of an optical path to filter the incoming light to allow frequencies of interest to pass while reflecting other frequencies of light. Transmission line theory can be applied to metallic meshes to understand how they work and the overall light transmission properties of groups of metallic meshes grouped together. Modeling the properties of these metallic meshes allows for reliable manufacture of filters with the desired transmission properties.