Analysis of high-resolution spectra from a hybrid interferometric/dispersive spectrometer

TL;DR

This paper presents a mathematical reconstruction technique for a compact hybrid spectrometer that achieves high spectral resolution and accurate peak intensity measurements, enabling portable applications with isotopic specificity.

Contribution

A novel mathematical method to reconstruct high-resolution spectra from a hybrid interferometric/dispersive spectrometer, enhancing resolution without increasing instrument size.

Findings

Achieved over tenfold increase in spectral resolution.

Accurately measured Hg doublet ratio consistent with literature.

Demonstrated potential for portable isotopic spectroscopic applications.

Abstract

To more fully take advantage of a low-cost, small footprint hybrid interferometric/dispersive spectrometer, a mathematical reconstruction technique was developed to accurately capture the high-resolution and relative peak intensities from complex spectral patterns. A Fabry-Perot etalon was coupled to a Czerny-Turner spectrometer, leading to increased spectral resolution by more than an order of magnitude without the commensurate increase in spectrometer size. Measurement of the industry standard Hg 313.1555/313.1844 nm doublet yielded a ratio of 0.682, which agreed well with an independent measurement and literature values. The doublet separation (29 pm) is similar to the U isotope shift (25 pm) at 424.437 nm that is of interest to monitoring nuclear nonproliferation activities. Additionally, the technique was applied to LIBS measurement of the mineral cinnabar (HgS) and resulted in a ratio of 0.682. This reconstruction method could enable significantly smaller, portable high-resolution instruments with isotopic specificity, benefiting a variety of spectroscopic applications.