Hadamard spectrometer for ultraviolet-visible spectrometry

Abstract

A Hadamard Transform Spectrometer (HTS) for use in the UV-Visible spectral region is described. The spectrometer is connected on-line to a digital computer to accumulate spectral information and to perform a Fast Hadamard Transform (FHT). The HTS system has been evaluated with several line sources as well as with a continuum source and for the atomic fluorescence measure-

Hadamard-Transform Fluorescence Excitation-Emission-Matrix Spectroscopy

“…The spectrally integrated transmission signal from each mask is recorded and the resultant vector array is decoded using the inverse of the Hadamard matrix. − HTs have also been widely used in several other spectroscopic techniques. They have found applications in NMR, MRI, UV–vis, Raman, and NIR spectroscopy. , All these applications were in one-dimensional spectroscopy, with the exception of a previously reported 2D Hadamard NMR technique . We believe that the HT provides a unique advantage in multidimensional spectroscopic techniques, i.e., when the intensities of two or more orthogonal spectra need to be modulated.…”

“…21−24 HTs have also been widely used in several other spectroscopic techniques. They have found applications in NMR, 25 MRI, 26 UV−vis, 27 Raman, 28 and NIR spectroscopy. 21,29 All these applications were in one-dimensional spectroscopy, with the exception of a previously reported 2D Hadamard NMR technique.…”

Systematic errors in Hadamard transform optics

“…4). Plankey et al 9 have described the effects produced by deliberate misalignment of a spectral encoding mask by 0.5 and 2.5 slit widths. As one would expect, the main result is an apparent spectral shift by 0.5 and 2.5 resolution elements, respectively, and an increase in spectral noise.…”

Applicability of TV-type multichannel detectors to spectroscopy

“…Multiplex spectrometric systems utilizing transform multiplex methods based upon Hadamard and Fourier mathematics have been successfully applied to IR spectroscopy with multiplex (SNR) advantage close to the theoretical. On the other hand, for UV-VIS, X-ray, electron, or any other type of spectroscopy in which the noise is statistical and dependent on the signal, multiplex transform detection offers a very limited advantage at best (1,2). Thus, the alternative multichannel approach, using multiple detectors monitoring discrete channels spatially separated from one another, remains the most promising choice.…”