Practical Beam Transport for the Planet Formation Imager (PFI)

TL;DR

This paper evaluates free-space vacuum pipe beam transport for the Planet Formation Imager, analyzing diffraction losses and proposing designs with pupil management to improve signal transmission in a future infrared interferometer.

Contribution

It provides a detailed analysis of diffraction losses in vacuum beam transport and introduces conceptual designs with pupil management for PFI.

Findings

Diffraction causes significant signal loss over long paths.

Pupil management techniques can mitigate diffraction losses.

Design considerations impact cost and feasibility of PFI beam transport.

Abstract

The Planet Formation Imager (PFI) is a future kilometric-baseline infrared interferometer to image the complex physical processes of planet formation. Technologies that could be used to transport starlight to a central beam-combining laboratory in PFI include free-space propagation in air or vacuum, and optical fibres. This paper addresses the design and cost issues associated with free-space propagation in vacuum pipes. The signal losses due to diffraction over long differential paths are evaluated, and conceptual beam transport designs employing pupil management to ameliorate these losses are presented and discussed.