Reflective Toraldo pupil for high-resolution millimeter-wave astronomy

Area of Science:

• Astronomy and Astrophysics
• Optics and Photonics
• Electromagnetics

Background:

• High-resolution astronomical instruments require precise control over electromagnetic wave propagation.
• Millimeter/submillimeter-wave astronomy benefits from advanced beam-shaping technologies to improve observational capabilities.
• Existing reflective optics may have limitations in achieving desired beam characteristics at these frequencies.

Purpose of the Study:

• To present a novel beam-shaping reflective surface for high-resolution millimeter/submillimeter-wave astronomy.
• To demonstrate the application of Toraldo's super-resolution principle in a practical optical device.
• To enable the transformation of Gaussian beams into flat-top beams with suppressed sidelobes.

Main Methods:

• Design based on Toraldo's super-resolution principle.
• Implementation using an annulated binary-phase coronae structure.
• Fabrication of a reflective Toraldo pupil device using mesh-filter technology for W-band operation.

Main Results:

• The fabricated device successfully reduced beam width upon reflection at oblique incidence.
• A sidelobe level lower than -10 dB was achieved.
• The device operates effectively in the W-band and is less than half a free-space wavelength thick.

Conclusions:

• The novel reflective Toraldo pupil is a viable solution for beam shaping in millimeter/submillimeter-wave astronomy.
• The design is scalable to higher frequency bands, including infrared.
• This technology can transform Gaussian beams into flat-top beams with significantly reduced sidelobes, improving instrument performance.