An innovative integral field unit upgrade with 3D-printed micro-lenses for the RHEA at Subaru

TL;DR

This paper presents a novel upgrade to an integral field unit using 3D-printed micro-lenses, enhancing light efficiency for high-resolution spectrographs in extremely large telescopes like Subaru.

Contribution

It introduces a new micro-lens system fabricated with 3D printing that significantly improves light injection efficiency in a high-resolution spectrograph.

Findings

Achieved up to ~77% of theoretical performance in lab tests.

Demonstrated high efficiency with 3D-printed micro-lenses on the injection fiber.

Validated the system's suitability for exoplanet and asteroseismology observations.

Abstract

In the new era of Extremely Large Telescopes (ELTs) currently under construction, challenging requirements drive spectrograph designs towards techniques that efficiently use a facility's light collection power. Operating in the single-mode (SM) regime, close to the diffraction limit, reduces the footprint of the instrument compared to a conventional high-resolving power spectrograph. The custom built injection fiber system with 3D-printed micro-lenses on top of it for the replicable high-resolution exoplanet and asteroseismology spectrograph at Subaru in combination with extreme adaptive optics of SCExAO, proved its high efficiency in a lab environment, manifesting up to ~77% of the theoretical predicted performance.