Microstructure technology for fabrication of metal-mesh grids

Motivated by the need for highly efficient far-IR Fabry-Perot étalons for airborne and space astronomy, we have developed a high-yield photolithographic technique for producing low-loss metal-mesh reflectors. We describe the production technique and report on the mesh flatness and uniformity. Optical measurements of meshes produced by this technique show that absorptivity of less than 1% with reflectivity of more than 98% was achieved at the longest wavelengths measured, which proved them to be significantly more efficient than commercially available meshes. This process can achieve wire widths that are less than the mesh thicknesses (typically 3 µm), which extends their applicability to wavelengths as short as ~ 20 µm without sacrificing mechanical strength for airborne and space-flight applications.