Chris Benson | Searcharxiv

arXiv2026

Experimental Demonstration of Double-Fourier Interferometer Imaging for Future Space-Based Far-Infrared Observatories

Far-infrared (FIR) astronomy is crucial for observing star formation, active galactic nuclei, and protoplanetary systems, but its effectiveness is severely limited by poor diffraction-limited spatial resolution. To overcome this limitation, a double-Fourier interferometer (DFI), which couples a spatial interferometer with a Fourier transform spectrometer, has been proposed to deliver high-resolution broadband spectral imaging. Despite various conceptual and prototype studies, a comprehensive demonstration of DFI capabilities has been lacking. In this study, we present the validation of key DFI observing techniques using a laboratory testbed operating in the 0.3 to 2.1 THz optical bandwidth. We detail the instrument's ideal response alongside necessary calibrations for intensity imbalances, non-linear phase errors, and phase-center offsets. Our experimental results successfully demonstrate aperture synthesis for both one- and two-dimensional targets, accurately recovering source geometries. Furthermore, we prove the instrument's sensitivity to spatially dependent spectral variations by utilizing a low-pass optical filter on extended sources. Finally, we validate wide-field imaging capabilities by combining data from independent pixels in a detector array, each sensitive to different regions of the source plane. The experimental data show significant agreement with theoretical predictions, with minor deviations attributed to optical aberrations and perspective effects. These laboratory demonstrations validate the DFI architecture as a highly capable and mature technology for future space-based FIR observatories.

astro-ph.IM↗

arXiv2026

The SPace-based InterFerometer Feasibility (SPIFF) Project: Enabling Future High-Resolution Astronomy Across the EM Spectrum

A plethora of astronomical science cases can only be achieved with high angular resolution observations, and we can expect the number of these to grow as astronomers are constrained by the size limitations of single-aperture space telescopes, making space-based interferometry inevitable. However, the enabling technologies do not have flight heritage at the system level, and the concept remains immature to much of the community, meaning no direct-detection synthetic-aperture space-based interferometer has yet flown and an opportunity exists for the UK to take a world leading role. Here we propose the SPace-based InterFerometry Feasibility (SPIFF) Project as a program to address both issues simultaneously by: 1) completing a thorough survey of the science cases across the EM spectrum that would directly benefit from, or be impossible without, space-based interferometry; 2) down selecting key requirements via a Science Traceability Matrix mapping exercise; 3) host a workshop for the UK astronomical community to consolidate these findings; 4) build a technology demonstration mission to raise TRL and achieve flight heritage of critical technologies. Such a program positions the UK as the partner of choice for any future NASA or ESA space-based interferometry mission, allowing the UK to lead groundbreaking scientific discoveries, while also directly benefiting the UK industrial base by advancing domestic exportable technologies and building direct synergy with other UK space priorities. Indeed, the UK is uniquely positioned to lead in space-based interferometry, possessing a rare trifecta of domestic strengths: world-class expertise in ground-based interferometry and space-based instrumentation; commercial entities developing mission-critical technologies; and scientists whose research spans the full range of science cases that would benefit directly from space-based interferometry.

astro-ph.IM↗