A microlens-array based pupil slicer and double scrambler for MAROON-X

TL;DR

This paper presents the design and construction of a microlens-array-based pupil slicer and double scrambler for the MAROON-X spectrograph, achieving high efficiency and improved fiber scrambling for precise radial velocity measurements.

Contribution

It introduces a novel dual MLA design for a 3X pupil slicer and double scrambler, enhancing efficiency and fiber scrambling in a high-precision spectrograph.

Findings

Achieved geometric efficiencies >85% with the MLA-based slicer.

Developed techniques for low-FRD rectangular fiber pseudo-slit.

Final design based on dual MLA with spherical and aspherical lenslets.

Abstract

We report on the design and construction of a microlens-array (MLA)-based pupil slicer and double scrambler for MAROON-X, a new fiber-fed, red-optical, high-precision radial-velocity spectrograph for one of the twin 6.5m Magellan Telescopes in Chile. We have constructed a 3X slicer based on a single cylindrical MLA and show that geometric efficiencies of >85% can be achieved, limited by the fill factor and optical surface quality of the MLA. We present here the final design of the 3x pupil slicer and double scrambler for MAROON-X, based on a dual MLA design with (a)spherical lenslets. We also discuss the techniques used to create a pseudo-slit of rectangular core fibers with low FRD levels.