  Ground-based millimeter and sub-millimeter telescopes are attempting to image
the sky with ever-larger cryogenically-cooled bolometer arrays, but face
challenges in mitigating the infrared loading accompanying large apertures.
Absorptive infrared filters supported by mechanical coolers scale
insufficiently with aperture size. Reflective metal-mesh filters placed behind
the telescope window provide a scalable solution in principle, but have been
limited by photolithography constraints to diameters under 300 mm. We present
laser etching as an alternate technique to photolithography for fabrication of
large-area reflective filters, and show results from lab tests of 500
mm-diameter filters. Filters with up to 700 mm diameter can be fabricated using
laser etching with existing capability.
