Abstract
A novel, to the best of our knowledge, beam-shaping reflective surface for high-resolution millimeter/submillimeter-wave astronomy instruments is presented. The reflector design is based on Toraldo's super-resolution principle and implemented with annulated binary-phase coronae structure inspired by the achromatic magnetic mirror approach. A thin, less than half a free-space wavelength, reflective Toraldo pupil device operated in the W-band has been fabricated using mesh-filter technology developed at Cardiff University. The device has been characterized on a quasi-optical test bench and demonstrated expected reduction of the beam width upon reflection at oblique incidence, while featuring a sidelobe level lower than -10dB. The proposed reflective Toraldo pupil structure can be easily scaled for upper millimeter and infrared frequency bands as well as designed to transform a Gaussian beam into a flat-top beam with extremely low sidelobe level.
Highlights
The pathway to high-resolution millimeter and submillimeter astronomy has been perceived as continuous increase of the aperture and size of the optical elements
Our design of the reflective Toraldo pupil stems from the classical problem of diffraction of a scalar field on an annular aperture cut in a perfect electric (PEC) conductor screen, and it follows the principle of the transmissive device discussed in [9,10]
Running a coarse parameter sweep with finite-element simulation, we found the optimum value of the scaling factor corresponding to a 30% reduction of full width at halfmaximum (FWHM) and sidelobe level (SLL) < −10 dB
Summary
The pathway to high-resolution millimeter and submillimeter astronomy has been perceived as continuous increase of the aperture and size of the optical elements. Super-resolution induced by optical diffraction with the aid of pupil filters has been a topic of extensive research in visiblelight and infrared astronomy for decades [5] This approach belongs to a class of methods aimed at shaping the PSF while keeping the spatial frequency bandwidth unchanged, [6]. In our previous report [22], we briefly discussed the feasibility of using a millimeter-wave metal-mesh metamaterial approach to design transmissive pupil masks for arbitrary amplitude and phase apodization (by pupil apodization we shall hereby mean shaping the point-spread function by varying amplitude and/or phase transmission in the entrance pupil of the telescope [5].) a new idea for a simple W-band reflective Toraldo pupil was outlined, inspired by the achromatic magnetic mirror concept, based on the reflection at the interface of materials with high and low dielectric constant (Dk), along with preliminary simulation and measurement results.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
