Spatial heterodyne spectroscopy for long-wave infrared: first measurements of broadband spectra

Long-wave IR sensing using spatial heterodyne spectroscopy

“…The polyimide results match the characteristic absorption features of this polymer material to a similar extent. 14 In summary, we have demonstrated that the emerging technique of SHS is viable for LWIR applications, especially when they benefit from some of the unique SHS properties. For example, observations from moving vehicles are of potential interest since they require rugged instrumentation without moving parts.…”

“…The interferometer's design passband covers the wavelength interval between 8.4 and 11.6 m, with a resolving power of approximately 500. 14 The complete spectrometer-see Figures 3(a) and 3(b)consists of a telescope, the interferometer, exit optics, and a cooled detector array. The telescope features a cooled passband filter and telecentric optics, which allow 1D imaging.…”

“…The focal plane of the mercury cadmium telluride array detector and the passband filter are the only cooled spectrometer parts. 14 To test the spectrometer's performance, we conducted transmittance measurements of methanol gas and a polyimide foil sample in a controlled laboratory environment. For the methanol measurements, we used a short gas cell filled with pure methanol.…”

Spatial heterodyne observations of water (SHOW) from a high-altitude airplane: characterization, performance, and first results

“…The most rigorous theoretical background of SHS is provided by Har-lander (1991Har-lander ( , 1992. Some of the more recent applications of the SHS technique for the remote sensing of the atmosphere can be found in Englert et al (2015). The framework and notation that is used here to describe the SHS technique follows directly from work that was performed at a US naval laboratory (Englert et al, 2004(Englert et al, , 2006.…”

“…For example, it is the first demonstration of the measurement of atmospheric water vapour using the SHS technique, specifically, using limb-scattered sunlight. In addition, the majority of the SHS instruments that have been developed have been used to observe well-isolated emission features, such as in the case of SHIMMER (Harlander et al, 2002), and the DASH type instruments that are used to remotely detect motions in the upper atmosphere using well isolated airglow emissions (Englert et al, 2007(Englert et al, , 2015(Englert et al, , 2017. Therefore, SHOW is also one of only several SHS instruments (Englert et al, 2009) that has been developed to observe absorption features over a broader spectral range.…”