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The desire for portable Raman spectrometers is continuously driving the development of novel spectrometer architectures where miniaturisation can be achieved without the penalty of a poorer detection performance. Spatial heterodyne spectrometers are emerging as potential candidates for challenging the dominance of traditional grating spectrometers, thanks to their larger etendue and greater potential for miniaturisation. This paper provides a generic analytical model for estimating and comparing the detection performance of Raman spectrometers based on grating spectrometer and spatial heterodyne spectrometer designs by deriving the analytical expressions for the performance estimator (signal-to-noise ratio, SNR) for both types of spectrometers. The analysis shows that, depending on the spectral characteristics of the Raman light and on the values of some instrument-specific parameters, the ratio of the SNR estimates for the two spectrometers ([Formula: see text]) can vary as much as by two orders of magnitude. Limit cases of these equations are presented for a subset of spectral regimes which are of practical importance in real-life applications of Raman spectroscopy. In particular, under the experimental conditions where the background signal is comparable or larger than the target Raman line and shot noise is the dominant noise contribution, the value of [Formula: see text] is, to a first order of approximation, dependent solely on the relative values of each spectrometer’s etendue and on the number of row pixels in the detector array. For typical values of the key instrument-specific parameters (e.g., etendue, number of pixels, spectral bandwidth), the analysis shows that spatial heterodyne spectrometer-based Raman spectrometers have the potential to compete with compact grating spectrometer designs for delivering in a much smaller footprint (10–30 times) levels of detection performance that are approximately only five to ten times poorer.

The intracluster medium (ICM) contains the vast majority of the baryonic matter in galaxy clusters and is heated to X-ray radiating temperatures. X-ray spectroscopy is therefore a key to understanding both the morphology and the dynamics of galaxy clusters. Here we recall crucial evolutionary problems of galaxy clusters unveiled by 19 years of high-resolution X-ray spectroscopy with the reflection grating spectrometer (RGS) on board XMM-Newton. Its exquisite combination of effective area, spectral resolution, and excellent performance over two decades has enabled transformational science and important discoveries such as the lack of strong cooling flows, the constraints on ICM turbulence, and cooling-heating balance. The ability of RGS to resolve individual ICM spectral lines reveals in great detail the chemical enrichment in clusters by supernovae and asymptotic giant branch stars. RGS spectra clearly show that the ICM plasma is overall in thermal equilibrium, which is unexpected given the wealth of energetic phenomena such as jets from supermassive black holes and mergers.

Carbon Observing Satellite (TanSat) is the first of Chinese experimental satellite for monitoring the CO2 column densities in the atmospheric, while identifying sources and sinks on regions scales. Three grating spectrometers are equipped on TanSat to measure the reflected sunlight in the 0.76μm O2A-band, 1.61μm weak CO2 band and 2.06μm strong CO2 band respectively. Three bands have high spectral resolution and signal to noise ratio (SNR), while their spectral and radiometric calibration have been reported in many articles. This paper describes the geometric calibration of the essential payload (ACGS) on the TanSat. In the assembly process, the flatness only in the spatial dimension is strictly controlled owing to the physical obstruction. The geometric deflection error in one band should be tested and corrected by adjusting the starting rows of different spectral samplings. Meanwhile, the alignment error among the three bands also need processing in the same way to ensure that the slits of the three bands were matched the corresponding geographic target. Finally, the geometric correction results of the thermal-vacuum testing suggested that the alignment accuracy is well enough to match the requirements.

This paper discusses the development of a cryogenic grating spectrometer that has been used to evaluate the performance of a post-dispersed polarizing FTS over the range of 285-500 µm.

The serpentine integrated grating spectrometer uses a meandering delay line and outcoupling grating rows to implement a crossed-dispersion wide-bandwidth integrated spectrometer with resolving power of 105 and 104 spectral bins in a few cm3 volume.

In the spectral analysis, it is very common to adjust the grating spectrometer's integration time to make it at the appropriate sensitivity, which can get high signal-to-noise ratio (SNR) and unsaturated spectrum. However, varying the integration time during measurement will introduce errors. The influence of varying spectrometer integration time on the spectral analysis was studied in this work, and a method was proposed to formulate a calibration model to inhibit the effect of different sensitivity spectrum due to different integration time. The strategy is to construct a model that is insensitive to the variation of integration time. This method involves the use of collected spectra under different integration time for the model establishment where the obtained model is found to satisfactorily inhibit the influence of integration time variation. An experiment was designed: Collecting the transmission spectra of Intra-lipid suspension by setting different integration time, the obtained spectral data were then processed by “Interactive-Validation method”that can evaluate the error caused by different integration, and processed by the“new modeling method”. The experimental results showed that when the integration time was varied to achieve high SNR spectra acquisition, the model established via the novel modeling strategy was clearly a viable method of improving its robustness by incorporating varying integration time, and it could well inhibit the error caused by integration time variation.

Branching fractions (BFs) of Ba I for 108 lines including 96 lines from 33 odd-parity levels with the configurations 5dnp (n = 6, 7, 8), 6snp (n = 7, 8, 11, 12), 6snf (n = 5, 6, 11, 16) and 5d4f, as well as 12 lines from 5 even-parity levels with the configurations 6snd (n=7, 9, 12) and 5d6d were measured using a high-resolution grating spectrometer with a hollow-cathode lamp. By combining the data of natural radiative lifetimes published in literature, the transition probabilities and oscillator strengths for these lines were also deduced, and the achieved results are in fair agreements with the previous ones.

This article first reviews the main characteristics of the High-Resolution Hyperspectral Sensor for carbon observation Grating Spectrometer (HRHS-GS) and discusses the impact of spectral resolution...

The Orbiting Carbon Observatory-3 (OCO-3) was launched on 04 May 2019 and provides a new perspective to the important task of studying atmospheric carbon dioxide (CO2) as well as solar-induced chlorophyll fluorescence (SIF), a bonus product, from space. The flight spare three-channel grating spectrometer instrument built for OCO-2 has been adapted for use on the International Space Station (ISS) as OCO-3 by modifying the entrance optics, using a new calibrator assembly, incorporating a two-axis pointing mirror assembly (PMA), and adding two context cameras. The ISS’ recessing orbit allows measurements to be collected from dawn to dusk in the equatorial to northern & southern mid-latitude regions and the PMA enables a new snapshot area mapping mode where ~80 km x ~80 km areas can be examined in more detail. The OCO-3 payload underwent an extensive ground test and calibration program in a 3 m diameter thermal vacuum chamber. The chamber has a port/window that allowed optical ground support equipment, including a heliostat, to illuminate the instrument under operating environmental conditions. The payload’s performance in space during the in-orbit checkout (IOC) period compares favorably with ground test results. Initial and not-yet-fully-calibrated retrieved estimates of the column-averaged dry air mole fraction of CO2 (XCO2) are reasonable when compared to ground-based measurements. SIF estimates show clear contrast between areas of high and low vegetation. There is high confidence that the three-year prime mission will deliver the data needed for science/research, data applications, and informed decision-making.

The present work deals with the broadening of rotational lines of the carbon monoxide 2–0 band by both argon and hydrogen chloride. A high resolution grating spectrometer with a spectral slit width of 0.07 cm(−1) was used, necessitating only a small correction in observed half-width values. Sufficiently small contributions of CO self-broadening were obtained by using long pathlength cells of 12 meters for CO-argon mixture and 1 meter for CO-HCl mixture. Half-width results, which are considered accurate to within ±5 percent, are presented in the form of a table and by a graph.

Calculations that achieve spectroscopic accuracy, i.e., at the level of ${10}^{\ensuremath{-}4}$ or better, are rare and typically restricted to few-electron systems. Here we present high-resolution grating spectrometer measurements of 11 $2{s}_{1/2}\text{\ensuremath{-}}2{p}_{3/2}$ transitions in neonlike ${\mathrm{Ge}}^{22+}$ that distinguish between two different implementations of the many-body perturbation theory (MBPT) method, including our own. The measurements show that our implementation of the MBPT method consistently achieves spectroscopic accuracy at the ${10}^{\ensuremath{-}4}$ level for all of the measured lines. Moreover, our calculations improve the ${10}^{\ensuremath{-}3}$ accuracy of prior MBPT calculations by an order of magnitude and allow us to make greatly improved predictions of the location of potential photopumped lines in ${\mathrm{Ge}}^{22+}$. The measurements also improve on previous measurements of $2{s}_{1/2}\text{\ensuremath{-}}2{p}_{3/2}$ transitions in fluorinelike ${\mathrm{Ge}}^{23+}$ and oxygenlike ${\mathrm{Ge}}^{24+}$. Measurements of $n=2\phantom{\rule{4.pt}{0ex}}\text{to}\phantom{\rule{4.pt}{0ex}}n=3$ transitions in ${\mathrm{Al}}^{7+}$, ${\mathrm{Al}}^{8+}$, and ${\mathrm{Al}}^{9+}$ are used to support our measurement accuracy at the ${10}^{\ensuremath{-}5}$ level.

As for detecting the atmosphere, this article proposed a spectrometer based on AOTF (Acoustic-Optic Tunable Filter) which spectrum range is 1500nm~2400nm. This scheme combined AOTF and reflection grating to realize the resolution of 0.1nm.

In this dissertation the work performed in the framework of the development of spectroscopic instrumentation for Ultrafast pulses in the XUV domain is presented. The activities on the installation, development and characterization of ultrafast instrumentation for handling, conditioning and detection of ultrashort pulses are described in detail. Moreover, the technical and scientific advances achieved, as well as the experimental results obtained, are reported and discussed.

Accepted: 2015-11-30, 資料番号: SA1160043000

Nitrogen dioxide is both a primary pollutant with direct health effects and a key precursor of the secondary pollutant ozone. This paper reports on the development, characterisation and test flight of the Atmospheric Nitrogen Dioxide Imager (ANDI) remote sensing system. The ANDI system includes an imaging UV/Vis grating spectrometer able to capture scattered sunlight spectra for the determination of tropospheric nitrogen dioxide (NO2) concentrations by way of DOAS slant column density and vertical column density measurements. Results are shown for an ANDI test flight over Leicester City in the UK on a cloud-free winter day in February 2013. Retrieved NO2 columns gridded to a surface resolution of 80 m × 20 m revealed hotspots in a series of locations around Leicester City, including road junctions, the train station, major car parks, areas of heavy industry, a nearby airport (East Midlands) and a power station (Ratcliffe-on-Soar). In the city centre the dominant source of NO2 emissions was identified as road traffic, contributing to a background concentration as well as producing localised hotspots. Quantitative analysis revealed a significant urban increment over the city centre which increased throughout the flight.

To optimize the accuracy of near-infrared non-invasive hemoglobin (Hb) clinical detection, high-performance instrument and prepossessing algorithm have been investigated. A near-infrared spectrophotometric system was constructed adopting InGaAs detector array with 16 pixels and plane grating spectrometer to obtain high signal noise ratio (SNR) spectral data. In our experiment, we applied the device independently to collect spectra data from 91 volunteers’ fingertips non-invasively. Two prediction tests were conducted to verify the effects of preprocessing algorithms improving the accuracy of near-infrared Hb detection and exclude the occasionality of satisfactory results in a single trial. Our non-invasive Hb detection methods were based on partial least squares (PLS). In each test, PLS, MSC coupled with PLS, DOSC coupled with PLS, three methods for non-invasive Hb detection, were analyzed respectively. The results of two trials showed that only DOSC & PLS performed excellently in both predictive ability and stability, obviously better than other two methods. Relative RMSEP was 6.16% in predicting test 1, 6.08% in predicting test 2, almost reaching the requirements of clinical application. It indicates that our independent-developed high-performance instrument and the method DOSC coupled with PLS are promising in non-invasive Hb detection clinical application.

We describe an experimental setup for observing the effect of optical feedback in an extended cavity diode laser. A simple grating spectrometer is used to observe the naturally occurring wavelength spread and mode spacing for the diode. When the diode is provided with optical feedback from a grating in the Littman-Metcalf configuration, the tunability of the diode is easily observed. This setup presents an intuitive and cost-effective method for demonstrating optical feedback in an advanced undergraduate laboratory setting.

The most common devices for the spectral dispersion of light are prism and grating spectrometers as well as diverse types of interferometers such as Fabry-Perot, Fizeau or Michelson interferometers.