Related Experiment Video
Updated: Aug 9, 2026

Characterization of Biological Absorption Spectra Spanning the Visible to the Short-Wave Infrared
Published on: January 10, 2025
Applicability of light-emitting diodes as light sources for active differential optical absorption spectroscopy
Christoph Kern1, Sebastian Trick, Bernhard Rippel
1Institute of Environmental Physics, University of Heidelberg, Im Neuenheimer Feld 229, 69120 Heidelberg, Germany. christoph.kern@iup.uni-heidelberg.de
Abstract:
We present what is to our knowledge the first use of light-emitting diodes (LEDs) as light sources for long-path differential optical absorption spectroscopy (LP-DOAS) measurements of trace gases in the open atmosphere. Modern LEDs represent a potentially advantageous alternative to thermal light sources, in particular to xenon arc lamps, which are the most common active DOAS light sources. The radiative properties of a variety of LEDs were characterized, and parameters such as spectral shape, spectral range, spectral stability, and ways in which they can be influenced by environmental factors were analyzed. The spectra of several LEDs were found to contain Fabry-Perot etalon-induced spectral structures that interfered with the DOAS evaluation, in particular when a constant temperature was not maintained. It was shown that LEDs can be used successfully as light sources in active DOAS experiments that measure NO2 and NO3 near 450 and 630 nm, respectively. Average detection limits of 0.3 parts in 10(9) and 16 parts in 10(12) respectively, were obtained by use of a 6 km light path in the open atmosphere.
Related Concept Videos
Atomic Absorption Spectroscopy: Radiation and Light Sources
Two common narrow-range 'line' sources used in AAS are hollow-cathode lamps (HCLs) and...
UV–Vis Spectrometers
Inductively Coupled Plasma Atomic Emission Spectroscopy: Instrumentation
There are three main types of inductively coupled plasma atomic emission spectroscopy (ICP-AES) instruments: sequential, simultaneous multichannel, and Fourier transform instruments, with the latter being less commonly used.
Atomic Absorption Spectroscopy: Overview
When irradiated by EMR of a particular wavelength, these...
Atomic Absorption Spectroscopy: Instrumentation
The atomizer used in AAS can be either a flame atomizer or an...
Atomic Emission Spectroscopy: Overview

