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As part of the payload of the 2016 ExoMars Trace Gas Orbiter (TGO) mission, the Nadir and Occultation for MArs Discovery (NOMAD) suite instrument has been observing the Martian atmosphere since March 2018. NOMAD is mainly dedicated to the study of trace atmospheric species taking advantage of a high-spectral resolution. We demonstrate that when NOMAD is observing in nadir mode, i.e., when the line-of-sight points to the centre of Mars, it can be also exploited to detect ice. In this study we present a method based on the investigation of nadir observations of the NOMAD infrared channel, acquired during Mars Years 34 and 35 (March 2018 to February 2021). We take advantage of the strong water ice absorption band at 2.7 µm by selecting the diffraction orders 167, 168, and 169. We derive the Frost and Clouds Index (FCI), which is a good proxy for ice mapping, and obtain latitudinal-seasonal maps for water ice clouds. FCI is sensitive to the Polar Hood clouds. Nevertheless, detections in the Aphelion Cloud Belt (ACB) are limited. This is consistent with previous observations showing different physical properties between the two main Martian atmospheric structures and making the ACB less detectable in the infrared. We hence derive the infrared nadir channel sensitivity limit for the detection of these clouds. [ABSTRACT FROM AUTHOR]

China's Fengyun-3D meteorological satellite launched in December 2016 carries the high-resolution greenhouse-gases absorption spectrometer (GAS) aimed at providing global observations of carbon dioxide (CO2). To date, GAS is one of the few instruments measuring CO2 from the near-infrared spectrum. On orbit, the oxygen (O2) A band suffers a disturbance, and the signal-to-noise ratio (SNR) is significantly lower than the nominal specification. This leads to difficulties in the retrieval of surface pressure and hence a degradation of the retrieval of the column-averaged CO2 dry air mole fraction (XCO2) if a full physics retrieval algorithm is used. Thus, a fast CO2 inverse method, named semi-physical statistical algorithm, was developed to overcome this deficiency. The instrument characteristics, the semi-physical statistical algorithm, and the results of comparison with ground-based measurements over land were introduced in this paper. XCO2 can be obtained from three bands, namely, the O2 A, weak CO2, and strong CO2 bands, with compensation from the Medium Resolution Spectral Imager-2 (MERSI-2) products, ECMWF Reanalysis v5 (ERA-5) data, and Total Carbon Column Observing Network (TCCON) data. The eigenvectors of covariance matrices and the least square fits were used to derive retrieval coefficients and yield cloud-free solutions. In addition to the GAS radiance, some key factors necessary for the accurate estimations of XCO2 were also taken as input information (e.g., air mass, surface pressure, and a priori XCO2). The global GAS XCO2 restricted over land was compared against the simultaneously collocated observations from TCCON. The retrieval algorithm can mitigate the issue caused by the low SNR of the O2 A band to a certain extent. Overall, through site-by-site comparisons, GAS XCO2 agreed well with the average precision (1σ) of 1.52 ppm and bias of −0.007 ppm. The seasonal variation trends of GAS XCO2 can be clearly seen at TCCON sites on the 1-yr timescale. [ABSTRACT FROM AUTHOR]

Motivated by applications in mobile optical sensing, ultracompact high‐resolution integrated spectrometers have attracted much interest. Here, a high‐resolution integrated speckle spectrometer, comprising a linear coherent network formed by mutually coupled Mach–Zehnder interferometers and nonidentical microring resonators, is proposed and demonstrated. Deep‐etched grating lines used as mirrors on the edges of the coherent network increase the effective optical path lengths. The speckle spectrometer is realized on a silicon nitride platform, operating at 776 nm central wavelength. The eight‐in−eight‐out linear coherent network provides 64 physical channels. Fine spectral lines separated by 20 pm are experimentally resolved within a device footprint of 520 µm × 220 µm. Compressive sensing is achieved for sparse spectra over a wide optical bandwidth. Up to 600 distinctive wavelength channels can be reconstructed from the 64 physical channels, giving 12 nm operating bandwidth. Both sparse spectra and continuous spectra are well reconstructed experimentally. The integrated speckle spectrometer has great potential for use in future biosensing and bioimaging applications where high spectral resolution is desired. [ABSTRACT FROM AUTHOR]

As part of the payload of the 2016 ExoMars Trace Gas Orbiter (TGO) mission, the Nadir and Occultation for MArs Discovery (NOMAD) suite instrument has been observing the Martian atmosphere since March 2018. NOMAD is mainly dedicated to the study of trace atmospheric species taking advantage of a high-spectral resolution. We demonstrate that when NOMAD is observing in nadir mode, i.e., when the line-of-sight points to the centre of Mars, it can be also exploited to detect ice. In this study we present a method based on the investigation of nadir observations of the NOMAD infrared channel, acquired during Mars Years 34 and 35 (March 2018 to February 2021). We take advantage of the strong water ice absorption band at 2.7 µm by selecting the diffraction orders 167, 168, and 169. We derive the Frost and Clouds Index (FCI), which is a good proxy for ice mapping, and obtain latitudinal-seasonal maps for water ice clouds. FCI is sensitive to the Polar Hood clouds. Nevertheless, detections in the Aphelion Cloud Belt (ACB) are limited. This is consistent with previous observations showing different physical properties between the two main Martian atmospheric structures and making the ACB less detectable in the infrared. We hence derive the infrared nadir channel sensitivity limit for the detection of these clouds.

We present the High-Rigidity Spectrometer (HRS) planned at the Facility for Rare Isotope Beams (FRIB). The current status of the layout and the ion-optical design of the HRS is discussed. [ABSTRACT FROM AUTHOR]

In this study, experimental demonstration of a static Fourier transform spectrometer (static-FTS), based on division of the spectrum into multiple narrowband signals, is presented. The bandpass sampling technique used in this novel spectrometer solves the Nyquist sampling rate limitations and enables recording of wideband spectrum in high resolution. The proposed spectrometer not only has the potential of operating in a wide spectral range, but also has a resolution potential better than 2 cm-1. [ABSTRACT FROM AUTHOR]

The Atmospheric Chemistry Suite (ACS) package is an element of the Russian contribution to the ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission. ACS consists of three separate infrared spectrometers, sharing common mechanical, electrical, and thermal interfaces. This ensemble of spectrometers has been designed and developed in response to the Trace Gas Orbiter mission objectives that specifically address the requirement of high sensitivity instruments to enable the unambiguous detection of trace gases of potential geophysical or biological interest. For this reason, ACS embarks a set of instruments achieving simultaneously very high accuracy (ppt level), very high resolving power (>10,000) and large spectral coverage (0.7 to 17 μm—the visible to thermal infrared range). The near-infrared (NIR) channel is a versatile spectrometer covering the 0.7–1.6 μm spectral range with a resolving power of ∼20,000. NIR employs the combination of an echelle grating with an AOTF (Acousto-Optical Tunable Filter) as diffraction order selector. This channel will be mainly operated in solar occultation and nadir, and can also perform limb observations. The scientific goals of NIR are the measurements of water vapor, aerosols, and dayside or night side airglows. The mid-infrared (MIR) channel is a cross-dispersion echelle instrument dedicated to solar occultation measurements in the 2.2–4.4 μm range. MIR achieves a resolving power of >50,000. It has been designed to accomplish the most sensitive measurements ever of the trace gases present in the Martian atmosphere. The thermal-infrared channel (TIRVIM) is a 2-inch double pendulum Fourier-transform spectrometer encompassing the spectral range of 1.7–17 μm with apodized resolution varying from 0.2 to 1.3 cm−1. TIRVIM is primarily dedicated to profiling temperature from the surface up to ∼60 km and to monitor aerosol abundance in nadir. TIRVIM also has a limb and solar occultation capability. The technical concept of the instrument, its accommodation on the spacecraft, the optical designs as well as some of the calibrations, and the expected performances for its three channels are described. [ABSTRACT FROM AUTHOR]

ACS is a set of spectrometers for atmospheric studies (Atmospheric Chemistry Suite). It is one of the Russian instruments for the Trace Gas Orbiter (TGO) of the Russian-European 'ExoMars' program. The purpose of the experiment is to study the Martian atmosphere by means of two observations regimes: sensitive trace gases measurements in solar occultations and by monitoring the atmospheric state during nadir observations. The experiment will allow us to approach global problems of Mars research such as current volcanism, and the modern climate status and its evolution. Also, the experiment is intended to solve the mystery of methane presence in the Martian atmosphere. Spectrometers of the ACS set cover the spectral range from the near IR-range (0.7 μm) to the thermal IR-range (17 μm) with spectral resolution λ/Δλ reaching 50000. The ACS instrument consists of three independent IR spectrometers and an electronics module, all integrated in a single unit with common mechanical, electrical and thermal interfaces. The article gives an overview of scientific tasks and presents the concept of the experiment. [ABSTRACT FROM AUTHOR]

We present two spectral-domain interferometric techniques for measuring the wavelength dependence of the group optical path difference (OPD) between the LPy01 and LPy11 modes of a bow–tie optical fibre. One technique utilizes a set-up comprising a white-light source, a tandem configuration of a Michelson interferometer with a two-mode optical fibre under test and a low-resolution spectrometer. In the set-up we record a series of the spectral interferograms for measuring directly the dispersion of the intermodal group OPD. The other technique utilizes a set-up comprising a superluminescent diode (SLD), a two-mode optical fibre under test and a high-resolution spectrometer. In the set-up we record a single spectral interferogram for determining the dispersion of both the overall phase with 2π ambiguity and the intermodal group OPD. The experimental results obtained by both measurement techniques are compared each other confirming good agreement. [Copyright &y& Elsevier]

Chemiluminescence reaction efficiently produces light, and that is where its scientific importance lies. For investigating the reaction in live fireflies, we introduce a few protocols that exert light emission at different temperatures and in different color sectors. From the changes in the peak position and the duration of flashes, the light can be characterized. As the firefly emits in green, yellow, and red color sectors, three color-filters are used for getting emissions in these three regions. Emission spectra are recorded in a high-resolution spectrometer, and flashes are obtained in an oscilloscope, after amplification in a photo multiplier tube, in the range of temperature 20-40 °C., (© 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

• Laser induced breakdown spectroscopy with high resolution. • Interference of Fe II atomic line for overestimation of carbon. • Fe I atomic line rationed with Fe II atomic line. • New test strategy through the calibration of Fe II atomic line. Laser-induced breakdown spectroscopy (LIBS) has been used for soil carbon (C) estimation by detecting the 247.8561 nm line of atomic carbon (C I). However, the Fe II line at 247.8572 nm interferes with the LIBS C measurement, resulting in C content overestimation. Due to the resolution limitation of common LIBS instruments, Fe II could not be identified and eliminated spectroscopically, and in natural soil the conventional method confirming constant emission intensity ratio of two Fe emission lines (Fe I line at 247.8572 nm and another Fe line which the upper energy level close or equal to the former) could not be used directly. Thus, in order to obtain the C content in soil, a high-resolution spectrometer (0.012 nm resolution) was employed to identify the C and Fe emission lines near 247.8561 nm in the standard reference soils 2709a (San Joaquin Soil) and 2711a (Montana II soil). For interference correction the emission line of Fe at 249.7819 nm was selected due to its constant ratio with delay time, and the least square method was employed to obtain the β coefficient of Fe 247.8572 nm emission line and the α coefficient of C 247.8561 nm emission line. The results demonstrated that suitable emission lines near 247.8561 nm could be identified using the high-resolution spectrometer, and the Fe interference could be reduced, even if the pure Fe 247.8572 nm intensity was unknown for the soil sample. The coefficient of α = 1600 and β = 3.02 were calculated from the case study and then the C content was corrected. With the Fe interference, the percentage of overestimated C was in the range of 15% to 58% in the used soil samples. This method minimizes C overestimation, and is less affected by soil heterogeneity and matrix effects, demonstrating its potential use in soil C quantification. [ABSTRACT FROM AUTHOR]