Design Of Spectrometer Research Articles

Mobile Raman spectrometry on Scorpio 7 rover

This article describes the design of the mobile Raman spectrometer of the Scorpio 7 rover. It was constructed to study the organic content of soil samples taken during the Rover Challenge series of Mars rover competitions. The basic theoretical issues that are used in Raman spectroscopy are described. Design assumptions and requirements for the construction and control software of the spectrometer during its use on board the Scorpio 7 Mars rover, constructed by the OFF-ROAD Scientific Association at the Wroclaw University of Technology, are discussed. Measurements of Raman spectra carried out by the Raman spectrometer installed in the research module of the Scorpio 7 rover are presented.

Design and Construction of a Teaching Mass Spectrometer and Its Application in Experimental Teaching

Design and Construction of a Teaching Mass Spectrometer and Its Application in Experimental Teaching

Low-cost spectrometer design for ultra-high resolution spectral domain optical coherence tomography

Low-cost spectrometer design for ultra-high resolution spectral domain optical coherence tomography

Mid-infrared Frequency Modulation Detection of HCN and Its Reaction with O Atoms behind Shock Waves.

Hydrogen cyanide (HCN) is the primary cyanide species in combustion processes and plays a key role in the formation of NOx in the combustion of fossil fuels, nitrogen-containing biofuels, and blended hydrocarbon-ammonia mixtures. Robust, sensitive, and time-resolved in situ laser diagnostic methods are needed to gain insight into the combustion chemistry of HCN. Mid-infrared frequency modulation spectroscopy (MIR-FMS) has recently been established as such a quantitative technique for HCN detection behind shock waves. With a minimum detectable fractional absorption of 2 × 10-4 at a time resolution of 5 μs, an improved spectrometer design enabled the detection of HCN behind shock waves down to the ppm mole fraction level. An Allan noise analysis revealed that a further improvement toward shot-noise limited detection should be possible when fast mid-infrared photodetectors with a higher saturation limit will become available. HCN kinetic profiles in the presence of O(3P) atoms from thermal N2O decomposition have been measured in the temperature range 1448 K < T < 1954 K. The determined total rate constants for the key HCN oxidation reaction HCN + O, k/(cm3 mol-1 s-1) = 1.88 × 1014 exp(-64.5 kJ mol-1/RT)(+28%, -37%), turn out to be largely consistent with previous measurements. These data complete the set of available rate constant studies, by now covering the temperature range 450 K < T < 2500 K and relying on the detection of almost all feasible reactant and product species.

Development of a single sphere neutron spectrometer using α-Al2O3:C based optically stimulated luminescence detectors

A multi-shell single sphere moderating assembly has been designed and developed to measure the neutron spectra in which the optically stimulated luminescence (OSL) detector pairs (Al2O3:C + 6, 7LiF) were used. The response matrix of OSL detectors, covering 11 energy decades (from thermal to 100 MeV neutrons) at different depths of the sphere, was generated using FLUKA-Monte Carlo simulation. The testing and validation of the spectrometer was performed using 3 standard neutron sources, viz. 241AmBe, 252Cf and DT. Neutron spectra were generated using 2 different unfolding codes. The design of the moderating assembly has the flexibility of selecting the desired sphere size as per the end point energy of the neutron spectrum. This can be conveniently employed in the complex radiation environment around particle accelerators, where the time and the space for irradiations have limitations. The details of the spectrometer design, response matrix generation and unfolding results are presented here.

Design of ultracompact broadband focusing spectrometers based on diffractive optical networks.

We propose the inverse design of ultracompact, broadband focusing spectrometers based on adaptive diffractive optical networks (a-DONs). Specifically, we introduce and characterize two-layer diffractive devices with engineered angular dispersion that focus and steer broadband incident radiation along predefined focal trajectories with the desired bandwidth and nanometer spectral resolution. Moreover, we systematically study the focusing efficiency of two-layer devices with side length L=100μ m and focal length f=300μ m across the visible spectrum and demonstrate accurate reconstruction of the emission spectrum from a commercial superluminescent diode. The proposed a-DONs design method extends the capabilities of efficient multi-focal diffractive optical devices to include single-shot focusing spectrometers with customized focal trajectories for applications to ultracompact spectroscopic imaging and lensless microscopy.

The Design and Manufacturing of a Czerny-Turner Spectrometer and a Spherical Aberration Reduction Mechanism for the Spectrometer

One of the most important diagnostic tools for a better understanding of actual systems is the spectroscopic examination of the physical properties of plasma and other bright sources. Atomic transitions of optical wavelengths are frequently used in a range of plasma devices as indicators of plasma characteristics like temperature and density. The design and construction of an effective spectrophotometer were motivated by the requirements of our ongoing plasma physics research. One of the most crucial methods for figuring out the density and temperature of electrons is the optical spectroscopic emission method. This study focused on the design and production of a low-cost Cherny-Turner spectrometer that could be produced locally. Using a manual micrometer, the slitter's exact movement is managed. Two quartz concave mirrors, one with a focal length of 15.375 cm and the other with a focal length of 16.825 cm, were employed. The spherical aberration was then treated by lowering the angle of incidence and angle of diffraction as much as feasible. The spectrometer's light input was focused, and the mirror positions were calibrated. The positions of the mirrors were calibrated with the diffraction grating to the location of the camera, first manually using a red laser light with a wavelength (650nm), and then using a CCD camera to locate the final image. With the movement of the diffraction grating to scan the wavelengths and analyze the light to its original components.

A lightweight broadband cavity-enhanced spectrometer for NO2 measurement on uncrewed aerial vehicles

Abstract. We describe the design and performance of a lightweight broadband cavity-enhanced spectrometer for measurement of NO2 on uncrewed aerial vehicles and light aircraft. The instrument uses a light-emitting diode (LED) centered at 457 nm, high-finesse mirrors (reflectivity =0.999963 at 450 nm), and a grating spectrometer to determine optical extinction coefficients between 430 and 476 nm, which are fit with custom spectral fitting software and published absorption cross sections. The instrument weighs 3.05 kg and has a power consumption of less than 35 W at 25 ∘C. A ground calibration unit provides helium and zero air flows to periodically determine the reflectivity of the cavity mirrors using known Rayleigh scattering cross sections. The precision (1σ) for laboratory measurements is 43 ppt NO2 in 1 s and 7 ppt NO2 in 30 s. Measurement of air with known NO2 mixing ratios in the range of 0–70 ppb agreed with the known values within 0.3 % (slope =0.997±0.007; r2=0.99983). We demonstrate instrument performance using vertical profiles of the NO2 mixing ratio acquired on board an uncrewed aerial vehicle between 0 and 110 m above ground level in Boulder, Colorado.

The design of high energy direct geometry chopper spectrometer at CSNS

The High energy Direct geometry spectrometer (HD) is a direct geometry time-of-flight chopper spectrometer currently under construction, and it will be the first inelastic neutron scattering instrument at the China Spallation Neutron Source. With its high neutron flux and a 160° angular coverage of 3 m long position-sensitive 3He detectors, the spectrometer will mainly be used to probe inelastic signals of novel spin and lattice dynamics in condensed matters and functional materials. The HD spectrometer is equipped with three switchable Fermi slit packages providing monochromation for both thermal and epithermal neutrons from 10 meV to 1500 meV, as well as a high-resolution repetition-rate multiplication (RRM) mode using curved slits. A special feature as a strict single incident energy mode can be provided using the combination of specially designed disk choppers and Fermi choppers. The design of the HD spectrometer is discussed in details.

Design of a μSR spectrometer with ultrahigh arrays at China Spallation Neutron Source

A new muon source has been proposed to conduct muon spin rotation/relaxation/ resonance (μSR) measurements at China Spallation Neutron Source (CSNS). Only 1 Hz of the CSNS proton beams (25 Hz in total) will be allocated for muon production. To make better use of muons in every pulse, an ultrahigh-array μSR spectrometer (UHAM) with thousands of detector channels is under design. Due to such a high granularity of detectors, multiple counting events generated from particle scattering or spiral motions of positrons in a strong longitudinal field should be carefully considered in the design. Six different structures were modeled and simulated based on two types of angular orientations (parallel arrangement and pointing arrangement) and three kinds of spectrometer geometries (cylinder, cone and sphere). A quality factor, Q, was proposed to evaluate the performance of these structures by integrating their impacts on the overall asymmetry, the counting rate and the percentage of multiple counts. According to the simulation, the conical structure with detectors pointing to the sample has the highest Q in both zero field and longitudinal field. The results also show that all kinds of structures cannot be operated under strong longitudinal fields with a strength over 2 T. The full simulation of a μSR spectrometer can provide good guidance for the construction of the UHAM in the upcoming upgrade of CSNS.

Solar-induced chlorophyll fluorescence imaging spectrometer: design, manufacture, and evaluation.

A scientific imaging spectrometer has been presented for the observation of solar-induced chlorophyll fluorescence of vegetation in NIR waveband, which may provide a new method to scale SIF application from leaf to canopy for the research of terrestrial vegetation photosynthesis. The SIF imaging spectrometer accommodates a telescope with a medium spatial resolution (1 mrad) over a field of view of 20°, a high spectral resolution (0.3nm) to measure the fluorescence spectrum within two oxygen absorption bands (O2A and O2B), and a high numerical aperture (0.25) for high SNR. Both of transmission optical systems, with high etendue and dispersive prism-VPH grating (P-G) with high diffraction efficiency, have been utilized for the optical design of imaging spectrometer. The design and prototype present excellent optical performances as demonstrated by the latest simulation and calibration. The in-situ observation proves that the advanced SIF imaging spectrometer could provide precise fluorescence data. The instrument will highlight SIF signal retrieval strategies, techniques for field and airborne and satellite sensing, and applications of these capabilities in evaluation of photosynthesis and stress effects for fluorescence science.

Integrated photodetectors for compact Fourier-transform waveguide spectrometers

Extreme miniaturization of infrared spectrometers is critical for their integration into next-generation consumer electronics, wearables and ultrasmall satellites. In the infrared, there is a necessary compromise between high spectral bandwidth and high spectral resolution when miniaturizing dispersive elements, narrow band-pass filters and reconstructive spectrometers. Fourier-transform spectrometers are known for their large bandwidth and high spectral resolution in the infrared; however, they have not been fully miniaturized. Waveguide-based Fourier-transform spectrometers offer a low device footprint, but rely on an external imaging sensor such as bulky and expensive InGaAs cameras. Here we demonstrate a proof-of-concept miniaturized Fourier-transform waveguide spectrometer that incorporates a subwavelength and complementary-metal–oxide–semiconductor-compatible colloidal quantum dot photodetector as a light sensor. The resulting spectrometer exhibits a large spectral bandwidth and moderate spectral resolution of 50 cm−1 at a total active spectrometer volume below 100 μm × 100 μm × 100 μm. This ultracompact spectrometer design allows the integration of optical/analytical measurement instruments into consumer electronics and space devices.

Design of the High Rigidity Spectrometer at FRIB

A High Rigidity Spectrometer (HRS) has been designed for experiments at the Facility for Rare-Isotope Beams (FRIB) at Michigan State University (MSU). The HRS will allow experiments to be performed with the most exotic neutron-rich isotopes at high beam energies (≳100MeV/u). The HRS consists of an analysis beamline called the High-Transmission Beamline (HTBL) and the spectrometer proper called the Spectrometer Section. The maximum magnetic rigidity of the HRS is 8Tm, which corresponds to the rigidities at which rare-isotope beams are optimally produced at FRIB. The resolving power, angular acceptance, and momentum acceptance are set to match the anticipated scientific program. An ion-optical design developed for the HRS is described in detail, along with the specifications of the associated magnet and detector systems.

A design method for direct vision coaxial linear dispersion spectrometers.

A spectrometer design method based on the prism-prism-grating (PPG) dispersion module is proposed in this paper to correct the serious nonlinear dispersion that prism and grating spectrometers and other dispersive spectrometers suffer from. First, we determine the criteria for selecting the optical materials of the PPG module by analyzing the dispersion characteristics of prisms and gratings. Second, a loop traversal algorithm is used to optimize the system structure parameters after selecting optical materials. Next, the direct vision coaxial condition of the PPG module is derived according to basic optical principles and the geometrical relationship between optical elements. Then, the dispersion equation of the PPG module is used to establish the spectral linearity index of the system. Finally, combined with the design index, the structural parameters of the PPG module to meet the linear dispersion requirements are determined. A direct vision coaxial linear dispersion spectrometer is designed and realized under the condition that the working band is 400-990 nm, the deviation angle and offset of the emitted ray with a central wavelength of 695 nm with respect to the optical axis are 0, and the dispersion angle is not less than 15°. The results simulated by ZEMAX show that the actual simulation results are consistent with the theoretical calculation results, the spectral resolution of the spectrometer is less than 1.5 nm, and the spectral smile and keystone are less than 3.89% pixels. In the discussion section, the influences of the dispersion ability of optical materials and the incident angles of prisms and gratings on the spectral dispersion linearity of the PPG module are analyzed and studied. The universality of the spectrometer design method developed in this paper is discussed, and its universality is simulated and verified in the 1000-1600 nm and 1600-2200 nm bands. In addition, some advantages compared with other dispersion structures are analyzed.

Design of Compact Mid-Infrared Cooled Echelle Spectrometer Based on Toroidal Uniform-Line-Spaced (TULS) Grating.

A traditional flat-panel spectrometer does not allow high-resolution observation and miniaturization simultaneously. In this study, a compact, high-resolution cross-dispersion spectrometer was designed based on the theoretical basis of echelle grating for recording an infrared spectrum. To meet the high-resolution observation and miniaturization design requirements, a reflective immersion grating was used as the primary spectroscopic device. To compress the beam aperture of the imaging system, the order-separation device of the spectrometer adopted toroidal uniform line grating, which had both imaging and dispersion functions in the spectrometer. The aberration balance condition of the toroidal uniform line grating was analyzed based on the optical path difference function of the concave grating, and dispersion characteristics of the immersed grating and thermal design of the infrared lens were discussed based on the echelle grating. An immersion echelle spectrometer optical system consisting of a culmination system, an immersed echelle grating, and a converged system was used. The spectrometer was based on the asymmetrical Czerny-Turner and Littrow mount designs, and it was equipped with a 320 × 256 pixel detector array. The designed wavelength range was 3.7–4.8 μm, the F-number was 4, and the central wavelength resolution was approximately 30,000. An infrared cooling detector was used. The design results showed that, in the operating band range, the root implied that the square diameter of the spectrometer spot diagram was less than 30 μm, the energy was concentrated in a pixel size range, and the spectrometer system design met the requirements.

SuperSpec: On-Chip Spectrometer Design, Characterization, and Performance

SuperSpec is an integrated, on-chip spectrometer for millimeter and sub-millimeter astronomy intended to pave the way for large-scale, multi-beam spectrometer instruments. SuperSpec is demonstrating a three beam, dual-polarization instrument for observing star formation in distant galaxies on the Large Millimeter Telescope , a 50 m telescope on Volcan Sierra Negra in Mexico. SuperSpec provides moderate resolution ( $$R \sim 270-290$$ ) in the 1 mm atmospheric window (200–300 GHz) with a lithographically patterned filterbank on a 3.5 cm x 5.5 cm chip. The filterbank intended for deployment is implemented in niobium, fed by a lensed antenna, and using a extremely low-volume ( $$2.6 \mu m^3$$ ) titanium nitride lumped element kinetic inductor detectors (LEKIDs) as the sensors. The small size of the spectrometer and inherent multiplexibility of the kinetic inductance detectors will allow the future use of SuperSpec in larger, multi-pixel/multi-object spectrometers far beyond the three-pixel spectrometer being demonstrated soon. We report the design of the spectrometer, laboratory characterization of devices for the upcoming SuperSpec deployment. This involves laboratory testing of the filterbank spectral response, and observing noise in the TiN KIDs.

The Evaluation of Spectral Resolution in the Optical Design of a Czerny-Turner Spectrometer

In this study, we propose a method of evaluating the spectral resolution of crossed-asymmetric Czerny-Turner spectrometers by comparing the impact of different slit functions on the optical transfer function, and different slit widths, through simulation and experiments. The results show that, the Gaussian function is suitable for narrower slit widths, such as 25 μm, and the rectangle function or convolution of slit-scattering function with rectangle function is suitable for wider slit widths, such as 50 μm, 150 μm, and 200 μm. The proposed method can provide guidance in the evaluation of spectral resolution in the preliminary optical design process of spectrometers.

Electrically tunable two-dimensional heterojunctions for miniaturized near-infrared spectrometers

Miniaturized spectrometers are of considerable interest for their portability. Most designs to date employ a photodetector array with distinct spectral responses or require elaborated integration of micro & nano optic modules, typically with a centimeter-scale footprint. Here, we report a design of a micron-sized near-infrared ultra-miniaturized spectrometer based on two-dimensional van der Waals heterostructure (2D-vdWH). By introducing heavy metal atoms with delocalized electronic orbitals between 2D-vdWHs, we greatly enhance the interlayer coupling and realize electrically tunable infrared photoresponse (1.15 to 1.47 μm). Combining the gate-tunable photoresponse and regression algorithm, we achieve spectral reconstruction and spectral imaging in a device with an active footprint < 10 μm. Considering the ultra-small footprint and simple fabrication process, the 2D-vdWHs with designable bandgap energy and enhanced photoresponse offer an attractive solution for on-chip infrared spectroscopy.

Detection of Trace Explosives Using a Novel Sample Introduction and Ionization Method.

A novel sample introduction and ionization method for trace explosives detection is proposed and investigated herein, taking into consideration real-world application requirements. A thermal desorption sampling method and dielectric barrier discharge ionization (DBDI) source, with air as the discharge gas, were developed. The counter flow method was adopted firstly into the DBDI source to remove the interference of ozone and other reactive nitrogen oxides. A separated reaction region with an ion guiding electric field was developed for ionization of the sample molecules. Coupled with a homemade miniature digital linear ion trap mass spectrometer, this compact and robust design, with further optimization, has the advantages of soft ionization, a low detection limit, is free of reagent and consumable gas, and is an easy sample introduction. A range of common nitro-based explosives including TNT, 2,4-DNT, NG, RDX, PETN, and HMX has been studied. A linear response in the range of two orders of magnitude with a limit of detection (LOD) of 0.01 ng for TNT has been demonstrated. Application to the detection of real explosives and simulated mixed samples has also been explored. The work paves the path to developing next generation mass spectrometry (MS) based explosive trace detectors (ETDs).

A two-beam interferometer with the tuning of the interference pattern period by simulating its rotation

Two-beam interferometer with fixed mirrors and fixed recording media, analytical analysis of optical scheme and design of the construction are presented. Tuning of the spatial frequency of the interference pattern on the media is carried out by rotation simulation mechanism. A working sample device of interferometer based on a beam-splitting cube 20 mm in size and implementing the investigated concept has been created. In the device, a half of convergence angle of interfering beams with a diameter of 5 mm is tunable in the range from 11 to 19°, its value is setting using a degree scale with a resolution of 0.1°. The deviation of actual value of the angle through the scale reading is experimentally obtained in the device. It was found that the absolute error does not exceed 1%. Developed interferometer may be useful an instance in holographic (including liquid) materials studies, development a new design of static Fourier spectrometers and making the interference based lithography process.