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Title: Optimum telescope focal ratios for microlens-to-fiber coupled integral field spectrographs
We describe the optimum telescope focal ratio for a two-element, three-surface, telecentric image-transfer microlens-to-fiber coupled integral field unit within the constraints imposed by microoptics fabrication and optical aberrations. We create a generalized analytical description of the microoptics optical parameters from first principles. We find that the optical performance, including all aberrations, of a design constrained by an analytic model considering only spherical aberration and diffraction matches within ± 4 % of a design optimized by ray-tracing software such as Zemax. The analytical model does not require any compromise on the available clear aperture; about 90% mechanical aperture of hexagonal microlens is available for light collection. The optimum telescope f-ratio for a 200-μm core fiber-fed at f / 3.5 is between f / 7 and f / 12. We find the optimum telescope focal ratio changes as a function of fiber core diameter and fiber input beam speed. A telescope focal ratio of f / 8 would support the largest range of fiber diameters (100 to 500 μm) and fiber injection speeds (between f / 3 and f / 5). The optimization of the telescope and lenslet-coupled fibers is relevant for the design of high-efficiency dedicated survey telescopes, and for retrofitting existing facilities via introducing focal macro-optics to match the instrument input requirements.  more » « less
Award ID(s):
1814682
PAR ID:
10484820
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
SPIE Digital Library
Date Published:
Journal Name:
Journal of Astronomical Telescopes, Instruments, and Systems
Volume:
8
Issue:
02
ISSN:
2329-4124
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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