Microstructure technology for fabrication of metal-mesh grids.

Area of Science:

• Optics and Photonics
• Materials Science
• Astronomy Instrumentation

Background:

• Fabry-Perot étalons are crucial for airborne and space astronomy, requiring highly efficient far-infrared (far-IR) reflectors.
• Existing metal-mesh reflectors often have limitations in efficiency and applicability at shorter wavelengths.

Purpose of the Study:

• To develop a high-yield photolithographic technique for producing low-loss metal-mesh reflectors.
• To characterize the flatness, uniformity, and optical properties of the fabricated meshes.
• To create reflectors suitable for demanding airborne and space-flight applications.

Main Methods:

• A photolithographic technique was employed for high-yield production of metal-mesh reflectors.
• Fabricated meshes were assessed for flatness and uniformity.
• Optical measurements were conducted to determine absorptivity and reflectivity at far-IR wavelengths.

Main Results:

• The photolithographic technique successfully produced low-loss metal-mesh reflectors.
• Achieved absorptivity was less than 1% and reflectivity exceeded 98% at the longest measured wavelengths.
• The process allows for wire widths smaller than mesh thicknesses (approx. 3 µm), enabling use down to ~20 µm wavelengths.

Conclusions:

• The developed photolithographic technique yields significantly more efficient far-IR metal-mesh reflectors compared to commercial options.
• These reflectors maintain mechanical strength, extending their utility to shorter wavelengths for advanced astronomical instruments.
• This advancement supports the development of next-generation airborne and space-based far-IR astronomical observatories.