Limited Wavelength Research Articles

Cloud detection sample generation algorithm for nighttime satellite imagery based on daytime data and machine learning application

Highly accurate nighttime cloud detection in satellite imagery is challenging due to the absence of visible to near-infrared (0.38–3 μm, VNI) data, which is critical for distinguishing clouds from other ground features. Fortunately, Machine learning (ML) techniques can more effectively leverage the limited wavelength information and show high-accuracy cloud detection based on vast sample volume. However, accurately distinguishing cloud pixels solely through thermal infrared bands (8–14 μm, TIR) is challenging, and acquiring numerous, high-quality and representative samples of nighttime images for ML proves to be unattainable in practice. Given the thermal infrared radiation transmission process and the fact that daytime and nighttime have the same source of radiance in TIR, we propose a sample generation idea that uses daytime images to provide samples of nighttime cloud detection, which is different from the traditional sample construction methods (e.g., manually label, simulation and transfer learning method), and can obtain samples effectively. Based on this idea, nighttime cloud detection experiments were carried out for MODIS, GF-5 (02) and Himawari-8 satellites, respectively. The results were validated by the Lidar cloud product and manual labels and show that our nighttime cloud detection result has higher accuracy than MYD35 (78.17%) and the ML model trained by nighttime manual labels (75.86%). The accuracy of the three sensors is 82.19%, 88.71%, and 79.34%, respectively. Moreover, we validated and discussed the performance of our algorithm on various surface types (vegetation, urban, barren and water). The results revealed that the accuracy of the three sensors over barren was found to be poor and varied with surface types but overall high. Our study can provide a novel perspective on nighttime cloud detection of muti-spectral satellite imagery.

Spectroscopic characterisation of gravitationally lensed stars at high redshifts

Deep imaging of galaxy cluster fields have in recent years revealed tens of candidates for gravitationally lensed stars at redshifts z ≈ 1 − 6, and future searches are expected to reveal highly magnified stars from even earlier epochs. Multi-band photometric observations may be used to constrain the redshift, effective temperature Teff, and dust attenuation along the line of sight to such objects. When combined with an estimate of the likely magnification, these quantities may be converted into a constraint on the stellar luminosity and, for an adopted set of stellar evolutionary tracks, the initial stellar mass. Further characterisation is difficult, however, without spectroscopic observations, which at the typical brightness levels of high-redshift lensed stars becomes extremely challenging for even the largest existing telescopes. Here, we explore what spectral features one can realistically hope to detect in lensed stars with peak brightness in the range 26–28 AB mag, Teff = 4000 − 50 000 K, and redshifts z = 1 − 10, using spectroscopy with JWST and the forthcoming ELT. We find that a majority of detectable lines appear in the rest-UV range for stars with Teff ≥ 15 000 K. The strongest detectable spectral lines are the C IV λ1550 Å line and the Si IVλλ1393, 1403 Å-doublet at Teff = 30 000 K. For lower temperatures, the calcium H- and K-lines at Teff = 6000 K are among the most readily detectable. In limited wavelength ranges, ELT is expected to provide more sensitive spectroscopic observations, and with higher resolution than JWST. We find that variations in both mass-loss rate and metallicity lead to noticeable effects in the detectability of certain spectral lines with both JWST and ELT.

Influence of columnar versus vertical distribution of aerosol properties on the modulation of shortwave radiative effects

Quantifying the interaction of atmospheric aerosols with incoming solar radiation remains a challenge owing to the limitations associated with measuring aerosol optical properties. This study investigates how the distribution of aerosol properties, whether columnar or vertical, affects the aerosol radiative forcing (ARF) and heating rates (HRs) across different atmospheric layers under cloud-free conditions in the shortwave region. We also assess the atmospheric parameters, namely, pressure, temperature, water vapour density, and ozone density, from in-situ measurements, reanalysis data, and a standard tropical atmosphere to understand their impact on ARF and HR estimates across seasons. Our findings show that aerosol absorption is highest during monsoon, while it is lowest in the winter. Significant atmospheric warming due to aerosols resulted from the substantial cooling at the surface. Columnar properties of aerosols measured at limited or multiple wavelengths yield similar ARF and HR estimates, provided spectral dependency is considered using the Angstrom exponent across seasons. However, the vertical profiles of aerosol extinction, together with a constant single scattering albedo (SSA) along the atmospheric column versus an actual SSA profile, led to notable differences in ARF and HRs, specifically in pre-monsoon and monsoon periods. Free tropospheric aerosol absorption is underestimated when using columnar properties compared to vertical distribution, while boundary layer absorption is overestimated (> 10 Wm-2). The heterogeneity in aerosol types across atmospheric layers significantly influenced aerosol absorption, highlighting the importance of accurate vertical distribution information. HR profiles obtained with vertical distribution reflect the structure of aerosol extinction, whereas those estimated with columnar properties result in smoother profiles that fail to capture altitude gradients. Aerosol-induced HRs are higher within the boundary layer and free troposphere in the monsoon season for all scenarios of defined aerosol properties. These findings underscore the need for actual vertical profile measurements of aerosol properties to quantify aerosol radiation interaction.

Advancing on-chip Kerr optical parametric oscillation towards coherent applications covering the green gap

Optical parametric oscillation (OPO) in Kerr microresonators can efficiently transfer near-infrared laser light into the visible spectrum. To date, however, chromatic dispersion has mostly limited output wavelengths to >560 nm, and robust access to the whole green light spectrum has not been demonstrated. In fact, wavelengths between 532 nm and 633 nm, commonly referred to as the “green gap”, are especially challenging to produce with conventional laser gain. Hence, there is motivation to extend the Kerr OPO wavelength range and develop reliable device designs. Here, we experimentally show how to robustly access the entire green gap with Kerr OPO in silicon nitride microrings pumped near 780 nm. Our microring geometries are optimized for green-gap emission; in particular, we introduce a dispersion engineering technique, based on partially undercutting the microring, which not only expands wavelength access but also proves robust to variations in resonator dimensions. Using just four devices, we generate >150 wavelengths evenly distributed throughout the green gap, as predicted by our dispersion simulations. Moreover, we establish the usefulness of Kerr OPO to coherent applications by demonstrating continuous frequency tuning (>50 GHz) and narrow optical linewidths (<1 MHz). Our work represents an important step in the quest to bring nonlinear nanophotonics and its advantages to the visible spectrum.

Wafer‐Scale Fabrication of Broadband Sb2Se3 Photodetectors and their Multifunctional Optoelectronic Applications

AbstractLow‐dimensional van der Waals materials (vdWMs) have attracted worldwide interest on account of numerous advantages including self‐passivated surface, high carrier mobility, excellent flexibility, etc. Among multiple vdWMs, Sb2Se3 stands out due to its high light absorption coefficient, environmentally friendly components, excellent stability, and abundant reserve. However, limited effective wavelength range and unscalable preparation have been obstinate issues standing in the way of further development. Herein, pulsed‐laser deposition (PLD) has been developed for synthesizing Sb2Se3 nanofilms, and wafer‐scale deposition has been realized. The PLD‐derived Sb2Se3 photodetector demonstrates broadband photoresponse across UV to NIR. First‐principles calculations have determined that this is because the formation of Se vacancies can result in a reduction of the bandgap. Upon 635 nm illumination, an optimal responsivity of 2.68 A W−1 has been achieved, corresponding to an external quantum efficiency of 524% and a specific detectivity of 1.34 × 1012 Jones. Furthermore, the device manifests a short response/recovery time of ≈2/1 ms. Proof‐of‐concept broadband imaging as well as fitness monitoring (respiratory rate &amp; heart rate) have been realized. Profited from the scalable preparation, an array of Sb2Se3 photodetectors have been produced, exhibiting qualified device‐to‐device variation. On the whole, this study has depicted an attractive landscape for next‐generation integrated optoelectronics.

Hydrogen sulfide and metal-enriched atmosphere for a Jupiter-mass exoplanet.

As the closest transiting hot Jupiter to Earth, HD 189733b has been the benchmark planet for atmospheric characterization1-3. It has also been the anchor point for much of our theoretical understanding of exoplanet atmospheres from composition4, chemistry5,6, aerosols7 to atmospheric dynamics8, escape9 and modelling techniques10,11. Previous studies of HD 189733b have detected carbon and oxygen-bearing molecules H2O and CO (refs. 12,13) in the atmosphere. The presence of CO2 and CH4 has been claimed14,15 but later disputed12,16,17. The inferred metallicity based on these measurements, a key parameter in tracing planet formation locations18, varies from depletion19,20 to enhancement21,22, hindered by limited wavelength coverage and precision of the observations. Here we report detections of H2O (13.4σ), CO2 (11.2σ), CO (5σ) and H2S (4.5σ) in the transmission spectrum (2.4-5.0 μm) of HD 189733b. With an equilibrium temperature of about 1,200 K, H2O, CO and H2S are the main reservoirs for oxygen, carbon and sulfur. Based on the measured abundances of these three main volatile elements, we infer an atmospheric metallicity of three to five times stellar. The upper limit on the methane abundance at 5σ is 0.1 ppm, which indicates a low carbon-to-oxygen ratio (<0.2), suggesting formation through the accretion of water-rich icy planetesimals. The low oxygen-to-sulfur and carbon-to-sulfur ratios also support the planetesimal accretion formation pathway23.

Energy Transfer‐Assisted Color Conversion of Persistent Mechanoluminescence in RhB@SiO2/SrAl2O4:Eu,Dy System for Multilevel Information Encryption

AbstractPersistent mechanoluminescence (PML) is highly desirable for its ability to overcome transient‐emitting behavior, but its applications are hindered by the limited emission wavelengths. Herein, a universal chemical interlinkage‐assisted efficient energy transfer (ET) strategy is introduced to achieve color conversion from green to red in traditional PML materials. A straightforward chemical route to create the RhB@SiO2/SAOED system is established via covalent chemical interlinkage by depositing mesoporous silica‐encapsulated Rhodamine B (RhB) nanoparticles (RhB@SiO2) onto SrAl2O4:Eu, Dy (SAOED) particles. The resulting system exhibits a high ET efficiency of 53.5%. The multicolor PML of the RhB@SiO2/SAOED system remains visible to the naked eye for exceeding 28 s after mechanical stimulation. With this unique PML behavior, the RhB@SiO2/SAOED system demonstrates the potential applications ranging from visualized reading activities to multi‐mode anticounterfeiting. This universal PML color‐conversion strategy provides a new approach to high‐performance mechanical light energy‐conversion systems and may further inspire more diverse functional applications of classical PML materials.

Pd(II)-Porphyrin-sensitized smart star polymer photocatalysts: A light-harvesting strategy using fluorescence resonance energy transfer effects

Photochemistry has become a popular topic in the field of sustainability. In particular, photocatalysts are a promising method to deal with environmental pollution, but only a few light sources with limited wavelengths are utilized to activate photosensitizers. Herein, we broaden the range of activation wavelengths of porphyrin-core amphiphilic star polymer photocatalysts by light harvesting. The coumarin moiety was polymerized from the porphyrin core while maintaining the amphiphilic microenvironment of the star polymer. The fluorescence resonance energy transfer (FRET) between porphyrin and coumarin leads to the activation of photocatalysts under both UV-A and UV-B light. Moreover, the copolymer sequence and polymer swelling effects on the FRET efficiency are discussed. The amphiphilic star block copolymer exhibited superior energy transfer efficiency in polar solvents, and its photocatalytic activity was evaluated via 2,5-dimethylfuran (2,5-DMF) photooxidation.

A high internal heat flux and large core in a warm Neptune exoplanet.

Interactions between exoplanetary atmospheres and internal properties have long been proposed to be drivers of the inflation mechanisms of gaseous planets and apparent atmospheric chemical disequilibrium conditions1. However, transmission spectra of exoplanets have been limited in their ability to observationally confirm these theories owing to the limited wavelength coverage of the Hubble Space Telescope (HST) and inferences of single molecules, mostly H2O (ref. 2). In this work, we present the panchromatic transmission spectrum of the approximately 750K, low-density, Neptune-sized exoplanet WASP-107b using a combination of HST Wide Field Camera 3 (WFC3) and JWST Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI). From this spectrum, we detect spectroscopic features resulting from H2O (21σ), CH4 (5σ), CO (7σ), CO2 (29σ), SO2 (9σ) and NH3 (6σ). The presence of these molecules enables constraints on the atmospheric metal enrichment (M/H is 10-18× solar3), vertical mixing strength (log10Kzz = 8.4-9.0 cm2 s-1) and internal temperature (>345 K). The high internal temperature is suggestive of tidally driven inflation4 acting on a Neptune-like internal structure, which can naturally explain the large radius and low density of the planet. These findings suggest that eccentricity-driven tidal heating is a critical process governing atmospheric chemistry and interior-structure inferences for most of the cool (<1,000 K) super-Earth-to-Saturn-mass exoplanet population.

Effect of thermal annealing on the surface plasmon properties of gold and silver nanodisk structures fabricated by electron beam lithography

This study investigates the effect of thermal annealing on the surface plasmon resonance properties of gold and silver nanodisk structures fabricated by electron beam lithography. Despite no significant size change due to a nickel adhesion layer, thermal annealing at 500 °C notably altered surface plasmon resonance properties, especially in gold nanodisks, which showed peak blue-shifts and narrowing, indicating improved crystallinity. We fitted the peak shift by using an electromagnetic field analysis and discussed the changes in the dielectric function. The dielectric function of the simple Drude model was adopted, which was fitted to the values of the Lorentz Drude model in a limited wavelength region. While both silver and gold exhibited increased oscillation strength, only gold nanodisk structures showed a decrease in damping frequency. Increased oscillation strength indicated that these structures should be useful for selective enhancement of the light at specific wavelengths by a very simple heat treatment.

Generation of stable ultraviolet optical ring lattices using monolithic AlN metasurfaces for cooling atoms

Optical ring lattices containing multiple optical traps in a ring configuration have gradually evolved into indispensable tools in cold atom experiments. However, the conventional methods for generating optical ring lattices require bulky apparatus and work at a limited wavelength range. Recently, metasurfaces have emerged as promising ultra-compact platforms for the implementation of optical ring lattices. Here, we report the generation of ultraviolet optical ring lattices using monolithic AlN metasurfaces. The feasibility of trapping atom and atom-like systems in the optical ring lattices is validated through theoretical calculation of the optical forces using the dipole model. The adoption of AlN metasurfaces can reduce the size and cost of generating optical ring lattices and thus give rise to diverse applications such as transportable atom clocks.

Biomimetic NIR-II fluorescent proteins created from chemogenic protein-seeking dyes for multicolor deep-tissue bioimaging

Near-infrared-I/II fluorescent proteins (NIR-I/II FPs) are crucial for in vivo imaging, yet the current NIR-I/II FPs face challenges including scarcity, the requirement for chromophore maturation, and limited emission wavelengths (typically < 800 nm). Here, we utilize synthetic protein-seeking NIR-II dyes as chromophores, which covalently bind to tag proteins (e.g., human serum albumin, HSA) through a site-specific nucleophilic substitution reaction, thereby creating proof-of-concept biomimetic NIR-II FPs. This chemogenic protein-seeking strategy can be accomplished under gentle physiological conditions without catalysis. Proteomics analysis identifies specific binding site (Cys 477 on DIII). NIR-II FPs significantly enhance chromophore brightness and photostability, while improving biocompatibility, allowing for high-performance NIR-II lymphography and angiography. This strategy is universal and applicable in creating a wide range of spectrally separated NIR-I/II FPs for real-time visualization of multiple biological events. Overall, this straightforward biomimetic approach holds the potential to transform fluorescent protein-based bioimaging and enables in-situ albumin targeting to create NIR-I/II FPs for deep-tissue imaging in live organisms.

Efficient Photocatalytic Core–Shell Synthesis of Titanate Nanowire/rGO

Wide bandgap semiconductor-based photocatalysts are usually limited by their low solar energy conversion efficiency due to their limited absorption solar wavelength, their rapid surface recombination of the photogenerated electron–hole pairs, and their low charge-carrier mobility. Here, we report a novel stepwise solution synthesis for achieving a new photocatalytic core–shell consisting of a titanate nanowire/reduced graphene oxide shell (or titanate/rGO) 1D-nanocomposite. The new core–shell nanocomposite maximized the specific surface area, largely reduced the charge transfer resistance and reaction energy barrier, and significantly improved the absorption of visible light. The core–shell nanocomposites’ large on/off current ratio and rapid photo-responses boosted the photocurrent by 30.0%, the photocatalysis rate by 50.0%, and the specific surface area by 16.4% when compared with the results for the pure titanate nanowire core. Our numerical simulations support the effective charge separation on the new core–shell nanostructure, which can help further advance the novel photocatalysis.

Novel techniques for in situ estimation of shear-wave velocity and damping ratio through MASW testing part II: a Monte Carlo algorithm for the joint inversion of phase velocity and phase attenuation

SUMMARY This paper deals with in situ characterization of the small-strain shear-wave velocity VS and damping ratio DS from an advanced interpretation of Multi-channel Analysis of Surface Waves (MASW) surveys. A new approach based on extracting Rayleigh wave data using the CFDBFa method has been discussed in the companion paper. This paper focuses on mapping the experimental Rayleigh wave phase velocity and attenuation into profiles of VS and DS versus depth, which is achieved through a joint inversion procedure. The joint inversion of phase velocity and attenuation data utilizes a newly developed Monte Carlo global search algorithm, which implements a smart sampling procedure. This scheme exploits the scaling properties of the solution of the Rayleigh eigenvalue problem to modify the trial earth models and improve the matching with the experimental data. Thus, a reliable result can be achieved with a limited number of trial ground models. The proposed algorithm is applied to the inversion of synthetic data and of experimental data collected at the Garner Valley Downhole Array site, as described in the companion paper. In general, inverted soil models exhibit well-defined VS profiles, whereas DS profiles are affected by larger uncertainties. Greater uncertainty in the inverted DS profiles is a direct result of higher variability in the experimental attenuation data, the limited wavelength range at which reliable values of attenuation parameters can be retrieved, and the sensitivity of attenuation data to both DS and VS. Nonetheless, the resulting inverted earth models agree well with alternative in situ estimates and geological data. The results stress the feasibility of retrieving both stiffness and attenuation parameters from active-source MASW testing and the effectiveness of extracting in situ damping ratio estimates from surface wave data.

Cooperative correction method for distortion and dispersion of deflected field of view in Risley-prism bionic-human-eye imaging systems.

The Risley-prism imaging system (RPIS) is a powerful way to achieve bionic human eye imaging with great advantages on large field of view (FOV) and variable resolution imaging owing to the autonomous controlled deflection of light. But the imaging dispersion originating from nonlinear and uneven light deflection results in limited imaging wavelength that seriously hinders its application. The existing solutions for imaging dispersion mainly rely on the hardware, which generally has bulky structure and limited improvement on image. Besides, the existing image evaluation methods for dispersion are not suitable for RPIS due to inhomogeneous dispersion. Herein, this paper systematically analyzes the mechanism and characteristics of dispersion in the RPIS, and proposes a cooperative correction method for image distortion and dispersion of multiple-color imaging, achieving the elimination of distortion and dispersion simultaneously without changing the optical structure. A dispersion evaluation index based on Pearson's correlation coefficient (PCC) is also established, and the objectivity and validity of the index are proved by experiments. Furthermore, a kind of compact RPIS based on an RGB camera is built, and both indoor and outdoor experiments are conducted. The experimental results demonstrate that proposed algorithm has strong universality and robustness for various scenes and targets.

Identification of Counterfeit Tobacco using Attenuated Total Reflectance Fourier Transform Infrared, Raman, and Near-Infrared Spectroscopy

Counterfeit and illicit tobacco may contain potentially toxic organic impurities that result in adverse health effects for the consumer. Carcinogenic substances have been found in elevated concentrations in counterfeit tobacco. The current study explored swift and cost-effective methods, such as Fourier-transform infrared, Raman, and near-infrared spectroscopy to identify counterfeit tobacco products. Moreover, it also assessed the spectral quality based on range, number of peaks, maximum peak intensity, and signal-to-noise ratio. In spectral analysis, infrared exhibited superior quality over Raman and near-infrared with a higher signal-to-noise ratio. Near-infrared, although with a limited wavelength range, showed good quality. Raman, however, displayed poor spectral quality due to noise interference. Identification success varied with chemo-metric methods, with infrared correctly identifying four out of five counterfeit tobacco products and near-infrared identifying three out of five. Raman failed in identification, while infrared showed success with some mismatches using principal component analysis. Near-infrared and Raman successfully identified counterfeit tobacco, with near-infrared providing the most distinct separation. Quantification results varied across spectroscopy techniques and chemo-metric methods.

Functional Coupling of Biohybrid Photosynthetic Antennae and Reaction Center Complexes: Quantitative Comparison with Native Antennae.

Light-harvesting (LH) complexes in photosynthetic organisms absorb photons within limited wavelength ranges over a broad solar spectrum. Extension of the LH wavelength has been realized by attaching artificial fluorophores to LH complexes (biohybrid LH complexes) for complementing the limited-wavelength regions. However, how efficiently such fluorophores in biohybrid LH complexes function to drive the photocatalytic reaction center (RC) has not been quantitatively evaluated, specifically in comparison with native LH antenna complexes. In this study, we prepared various biohybrid LH1-RC complexes (from Rhodopseudomonas palustris), to quantitatively evaluate the LH activity of the attached external chromophores through a photocurrent generation reaction by LH1-RC on an electrode. For a direct comparison of the LH activity among the LH chromophores that were examined, we introduced the k1 term, which represents the extent of the functional coupling of LH and the photochemical reactions in the RC. We determined that the hydrophobic fluorophore ATTO647N attached to LH1 possesses the highest LH activity among the examined hydrophilic fluorophores such as Alexa647, and its activity is comparable to that of native LH1(-RC). The LH activity of LH2 (from Rhodoblastus acidophilus strain 10050) and its biohybrid LH2s were examined for the comprehensive assessment of their LH activity.

Self-Luminous Probe with One-Step Energy Conversion from Bioluminescence to NIR-IIb.

Self-luminous probes with near-infrared (NIR) emission are powerful tools for deep-penetration and autofluorescence-free imaging, owing to the joint optimization of both excitation and emission. However, the limited emission wavelength and requirement for multistep energy transfer limit its potency. In this study, the concept of direct wavelength conversion is established from visible light (vis) to NIR-IIb using an exquisitely designed sensitizer-activator ion pair. The manipulation of the doping hosts enables a pair of energy levels between the sensitizer and activator. Based on this a class of broadband vis-responsive nanocrystals with intense NIR-II emission is prepared. The stability and quantum yield (up to 7.4%) of the nanocrystals are further enhanced by ZnS passivation via coherent epitaxial growth. By coupling luciferase, the self-luminous probe can convert bioluminescence to NIR-IIb luminescence (>1500nm) through a one-step energy transfer. A maximum penetrable thickness of 6mm is achieved in the porcine tissue model. Collectively, the distinctive photon-conversion performance of this probe offers the prospect of high-resolution labeling of deep-seated lesions.

Rationally Engineered hCES2A Near-Infrared Fluorogenic Substrate for Functional Imaging and High-Throughput Inhibitor Screening.

Human carboxylesterase 2A (hCES2A) is an important endoplasmic reticulum (ER)-resident enzyme that is responsible for the hydrolytic metabolism or activation of numerous ester-bearing drugs and environmental toxins. The previously reported hCES2A fluorogenic substrates suffer from limited emission wavelength, low specificity, and poor localization accuracy, thereby greatly limiting the in situ functional imaging of hCES2A and drug discovery. Herein, a rational ligand design strategy was adopted to construct a highly specific near-infrared (NIR) substrate for hCES2A. Following scaffold screening and recognition group optimization, HTCF was identified as a desirable NIR fluorophore with excellent photophysical properties and high ER accumulation ability, while several HTCF esters held a high potential to be good hCES2A substrates. Further investigations revealed that TP-HTCF (the tert-pentyl ester of HTCF) was an ideal substrate with ultrahigh sensitivity, excellent specificity, and a substantial signal-to-noise ratio. Upon the addition of hCES2A, TP-HTCF could be rapidly hydrolyzed to release HTCF, a chemically stable product that emitted bright fluorescent signals at around 670 nm. A TP-HTCF-based biochemical assay was then established for the high-throughput screening of potent and cell-active hCES2A inhibitors from an in-house compound library. Furthermore, TP-HTCF displayed high imaging resolution for imaging hCES2A in living cells as well as mouse liver slices and tumor-xenograft mice. Collectively, this study demonstrates a rational strategy for developing highly specific fluorogenic substrates for an ER-resident target enzyme, while TP-HTCF can act as a practical tool for sensing hCES2A in living systems.

Grain Size Effects on UV–MIR (0.2–14 μm) Spectra of Carbonaceous Chondrite Groups

Carbonaceous chondrites are among the most important meteorite types and have played a vital role in deciphering the origin and evolution of our solar system. They have been linked to low-albedo C-type asteroids, but due to subdued absorption bands, definitive asteroid–meteorite linkages remain elusive. A majority of these existing linkages rely on fine-grained (typically < 45 μm) powders across a limited wavelength range in the visible to near-infrared (0.35–2.5 μm). While this is useful in interpreting the fine-grained regolith of larger main-belt objects like Ceres, recent spacecraft missions to smaller near-Earth asteroids (NEAs), such as Bennu and Ryugu, have shown that their surfaces are dominated by larger grain size material. To better interpret the surfaces of these smaller, carbonaceous NEAs, we obtained laboratory reflectance spectra of seven carbonaceous chondrite meteorite groups (CI, CM, CO, CV, CR, CK, C2-ungrouped) over the ultraviolet to mid-infrared range (0.2–14 μm). Each meteorite contained five grain size bins (45–1000 μm) to help constrain spectral grain size effects. We find a correlation between grain size and absolute reflectance, spectral slope, band depth, and the Christiansen feature band center. Principal component analysis of grain size variation illustrates a similar trend to lunar-style space weathering. We also show that the Bus–DeMeo asteroid taxonomic classification of our samples is affected by grain size, specifically shifting CM2 Aguas Zarcas from a Ch-type to B-type with increasing grain size. This has implications for the parent body of the OSIRIS-REx target, Bennu. With Aguas Zarcas, we present results from Hapke modeling.