Highly replicable, low-cost, portable, general-purpose, high-resolution spectrometer with applications in stellar studies and exoplanet science

Abstract

High-resolution spectrometers have proven to be an important tool for astronomical observations and continue to have an ever expanding set of applications, such as high resolution IFS (Integral Field Spectroscopy). With this in mind, we present an alternative approach to the design and construction of Echelle type spectrometers. The usual approach is to drive high resolving power through the use of large gratings and long focal length collimators, leading to great production costs in the order of $1,000,000. Our compact, proof-of-concept prototype, via the coupling of adaptive optics, achieves comparable performance and resolution; with a theoretical resolving power R<80,000 in the Vis-NIR regime (500nm-1μm) at a cost <$10,000. This is attained through the use of COTS (Commercially-Off-The-Shelf) and economically designed components. The overall device footprint is compact, measuring the size of a â€shoe-box', approximately 30cm×15cm. The spectrometer prototype is fibre-fed with a single 10μm fibre and follows a double-pass design-Applying a custom designed, 108.24mm focal length, collimating and re-focussing lens. The system follows an Echelle type design with high resolution achieved through the use of a compact R4 diffraction grating and a prism as the cross-disperser.