Optical Spectroscopy Techniques Research Articles

Characteristics of Lead and Sulfur Plasma Parameters by Optical Emission Spectroscopy

This study uses the optical emission spectroscopy (OES) technique to find the lead(Pb) and sulfur (S) plasma parameters employing a pulse of Nd: YAG laser (Q-switched 1064nm wavelength) and different laser energies of (400,500,600 and 700 mJ). The electron temperature Te (eV) is calculated using the Boltzmann-Plot method, and the electron density ne (cm-3)is determined by the Stark broadened way. Moreover, Debye length λD (cm) and plasma frequency ωp (Hz) are studied as a function of laser energy. An apparent increase was noted in the electron temperature of lead plasma and a decrease in sulfur plasma. The results also showed that each increase in the laser intensity causes an increase in the optical emission peaks. This experiment was carried out under atmospheric pressure.

Correlative Fluorescence and Raman Microscopy to Define Mitotic Stages at the Single-Cell Level: Opportunities and Limitations in the AI Era.

Nowadays, morphology and molecular analyses at the single-cell level have a fundamental role in understanding biology better. These methods are utilized for cell phenotyping and in-depth studies of cellular processes, such as mitosis. Fluorescence microscopy and optical spectroscopy techniques, including Raman micro-spectroscopy, allow researchers to examine biological samples at the single-cell level in a non-destructive manner. Fluorescence microscopy can give detailed morphological information about the localization of stained molecules, while Raman microscopy can produce label-free images at the subcellular level; thus, it can reveal the spatial distribution of molecular fingerprints, even in live samples. Accordingly, the combination of correlative fluorescence and Raman microscopy (CFRM) offers a unique approach for studying cellular stages at the single-cell level. However, subcellular spectral maps are complex and challenging to interpret. Artificial intelligence (AI) may serve as a valuable solution to characterize the molecular backgrounds of phenotypes and biological processes by finding the characteristic patterns in spectral maps. The major contributions of the manuscript are: (I) it gives a comprehensive review of the literature focusing on AI techniques in Raman-based cellular phenotyping; (II) via the presentation of a case study, a new neural network-based approach is described, and the opportunities and limitations of AI, specifically deep learning, are discussed regarding the analysis of Raman spectroscopy data to classify mitotic cellular stages based on their spectral maps.

Optical markers of magnetic phase transition in CrSBr

Here, we investigate the role of the interlayer magnetic ordering of CrSBr in the framework of ab initio calculations and by using optical spectroscopy techniques.

Bis-porphyrin tetragonal prisms assembled through Watson-Crick hydrogen bonding between complementary nucleobases

We report here on the self-assembly of two components, a Zn(II) porphyrin substituted with four lipophilic cytidines and a linear linker substituted with two guanosines, into a Watson-Crick hydrogen-bonded tetragonal prism. The corresponding ensemble, comprising two cofacial porphyrin macrocycles, exhibited similar supramolecular behavior as a reference cyclic tetramer previously studied by us. The establishment of strong G:C interactions in apolar chlorinated solvents was demonstrated by the chemical shift recorded for the relevant H-bonded protons. Most importantly, the hexacomponent prism assembly, when partially dissociated by the addition of the competing DMSO solvent, exhibited a slow exchange on the NMR timescale with the individual constituents, which is characteristic of kinetically stabilized discrete assemblies. Absorption, emission, and CD spectroscopy experiments revealed that the spectral features of the tetragonal prism were totally different from the ones recorded for the porphyrin and linker components, which also showed strong self-aggregation in apolar solvents. Temperature-dependent experiments, monitored by NMR and optical spectroscopy techniques, revealed remarkable thermodynamic stability for the prism assembly.

A numerical procedure for understanding the self-absorption effects in laser induced breakdown spectroscopy.

Optical emission spectroscopic techniques, such as laser-induced breakdown spectroscopy (LIBS), require an optimal state of plasma for accurate quantitative elemental analysis. Three fundamental assumptions must be satisfied in order for analytical results to be accurate: local thermodynamic equilibrium (LTE), optically thin plasma, and stoichiometric ablation. But real-life plasma often fails to satisfy these conditions, especially the optical thinness of plasma, resulting in the reabsorption of emitted radiation called self-absorption. To study the self-absorption effect, we simulated optically thick emission spectrum at typical laser-produced plasma conditions. The simulation of the spectrum involves four stages, including the estimation of the ratio of the number density of various ionisation states in the plasma using the Saha-Boltzmann equation, the peak intensity of a spectral line using the Boltzmann equation, the full-width half maxima of each spectral line using the Stark broadening method, and the generation of full spectra by providing a Lorentzian profile for each spectral line. Then self-absorption is applied to the simulated spectrum. We investigated the dependence of the self-absorption coefficient on the plasma temperature, optical path length, and element concentration in the sample. Self-absorption decreases with increased plasma temperature, whereas it increases with increasing optical path length and analyte concentration. We also investigated the role of self-absorption in quantitative analysis by calibration-free LIBS with and without resonance lines of the binary alloy (Mg 50% & Ca 50%). We observed a drastic reduction in error from 27% to 2% in the composition estimation when excluding resonance lines.

Retrieval and Regional Distribution Analysis of Ammonia, Sulfur Dioxide and Nitrogen Dioxide in the Urban Environment Using Ultraviolet DOAS Algorithm

Aiming at the in situ and mobile observation of urban environmental air pollution, a portable instrument using ultraviolet spectrum retrieval algorithm was developed based on the basis of Differential Optical Absorption Spectroscopy (DOAS) and multiple-pass cell technique. Typical trace gas pollutants, NH3, SO2, and NO2, were explored using their optical spectral characteristics in deep ultraviolet wavelength range from 210 to 215 nm. The gas concentration was retrieved by Lambert-Beer's law and nonlinear least square method. With an optimized optical alignment, the detection limits of NH3, SO2, NO2 were estimated to be 2.2, 2.3, and 36.2 ppb, respectively. The system was used in carrying out some cruise observations in Chengdu, China. During the entire period, the polluted gases showed varied distribution and typical daily average concentrations of NH3, SO2, NO2 were 23.2, 3.5, and 106.0 ppb, respectively. The contributions from different sources were analyzed combined with the HYSPLIT model. Results show that the portable DOAS system is a convenient and effective tool for regional distribution measurement and pollution source monitoring.

PDI-trityl dyads as photogenerated molecular spin qubit candidates.

Owing to their potential applications in the field of quantum information science, photogenerated organic triplet-radical conjugates have attracted an increasing amount of attention recently. Typically, these compounds are composed of a chromophore appended to a stable radical. After initialisation of the system by photoexcitation, a highly spin-polarised quartet state may be generated, which serves as a molecular spin qubit candidate. Here, we investigate three perylene diimide (PDI)-based chromophore-radical systems with different phenylene linkers and radical counterparts by both optical spectroscopy and transient electron paramagnetic resonance (EPR) techniques. Femtosecond transient absorption measurements demonstrate chromophore triplet state formation on a picosecond time scale for PDI-trityl dyads, while excited state deactivation is found to be slowed down considerably in a PDI-nitroxide analogue. The subsequent investigation of the coherent spin properties by transient EPR confirms quartet state formation by triplet-doublet spin mixing for all investigated dyads and the suitability of the two studied PDI-trityl dyads as spin qubit candidates. In particular, we show that using tetrathiaryl trityl as the radical counterpart, an intense spin polarisation is observed even at room temperature and quartet state coherence times of 3.0 μs can be achieved at 80 K, which represents a considerable improvement compared to previously studied systems.

Chemical Imaging – Is an Image Always Worth a Thousand Spectra?

Chemical images can be described as distribution maps that correlate the chemical information of an element or molecule, such as mass-to-charge ratio (m/z) or wavelength, with its intensity and/or concentration in a given sample. These images are usually obtained by mass spectrometry (MS) or optical spectroscopy techniques, where hundreds or thousands of spectra are initially acquired and dedicated image processing software is employed to construct and edit the final pictures, as well as selecting and annotating regions of interest in a sample, performing calibration procedures, etc. Mass spectrometry imaging (preferably abbreviated as MSI, to distinguish it from ion mobility spectrometry – IMS) is currently the most employed chemical imaging strategy, as can be noticed in the most recently published papers. Depending on the selected ionization technique, molecular or elemental images can be acquired. For molecular MSI, the classical matrix-assisted laser desorption/ionization (MALDI) is generally applied for imaging lipids, peptides and proteins, and the ambient ionization technique desorption electrospray ionization (DESI) is commonly applied for visualizing lipid distribution. In terms of elemental MSI, laser ablation inductively coupled plasma (LA-ICP) is undoubtedly the technique of choice, although nano-secondary ion mass spectrometry (nanoSIMS) can also be applied. Considering optical spectroscopy, the main techniques used nowadays are Raman and near-infrared radiation – NIR – spectroscopy for molecular imaging, and Synchrotron radiation X-ray fluorescence – SRXRF – and laser-induced breakdown spectroscopy – LIBS – for elemental imaging. Amongst these techniques, the best spatial resolutions are generally achieved by SRXRF (elemental imaging) and Raman spectroscopy (molecular imaging). Analytical chemistry advances in chemical imaging allow the acquisition of images with high spatial resolution, which is particularly interesting when studying specific regions or cell structures in a biological sample. For instance, in a Parkinson’s disease model, LA-ICP-MS images with good spatial resolution make the distinction of specific mouse brain regions possible and, consequently, the association of metal ion concentrations to each region,1 which is a relevant result considering micro-local metal speciation in neurodegenerative diseases. Nevertheless, there are some drawbacks in chemical imaging that demand further analytical development, such as the long analysis time and the lack of certified reference materials for quantitative analysis and method validation, as well as open-source software with advanced multivariate statistical analysis tools. Another obstacle to overcome concerns the integration of elemental and molecular imaging results. Since 2009, when one of the first review articles regarding the combination of these imaging approaches in a synergistic way was proposed by Becker and Jakubowski,2 until more recently described in reviews from 20203 and 2021,4 it has been possible to realize that there is still much work to be done in this field. This is mostly due to the fact that each imaging technique provides different spatial resolutions, making image superposition difficult, and also the absence of software and algorithms that allow the integration of different data sets in order to obtain trustworthy results and produce relevant study hypotheses. Besides that, the instrumentation for chemical imaging is rather costly and usually research groups are specialized in either molecular or elemental imaging. With these considerations, it is important to emphasize that the community involved in chemical imaging research should focus not only on the quality of the generated images in terms of resolution but also, if they are indeed worth a thousand spectra, on interpretation of the initial questions in a deep and holistic manner. After all, the main objective of chemical imaging is that the images represent how the process in question (disease, treatment, contamination, genetic modification, etc.) locally affects the system (biological, environmental, pharmaceutical sample) under study and, then, provide solutions for solving problems in different areas, such as forensic, environmental and life sciences.

PVC/PVP/SrTiO3 polymer blend nanocomposites as potential materials for optoelectronic applications

This paper presents, for the first time, the preparation and study of the thermal decomposition and optical properties of PVC/PVP/SrTiO3 polymer blend nanocomposites. The polymer films were characterized using X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), Raman, thermogravimetric analysis (TGA), and optical spectroscopy techniques. XRD spectra indicated semicrystalline structure of the PVC/PVP polymer blend and revealed cubic crystal structure of the SrTiO3 nanoparticles. The lattice constant of SrTiO3 was found to decrease from 2.79 to 2.75 Å upon increasing the concentration of the SrTiO3 nanoparticles in the blend to 0.6 wt%. The FTIR and Raman spectra revealed the strong interaction between PVC/PVP polymer blend and SrTiO3. The TGA analysis showed a slight enhancement of the polymer blend thermal stability. Moreover, the thermal kinetic parameters, such as activation energy, entropy and Gibbs free energy, of the polymer nanocomposites were lower than those of the pure PVC/PVP blend counterpart. The addition of SrTiO3 increased the optical absorption, energy gap, and linear refractive index. Furthermore, the optical susceptibility and nonlinear refractive index were significantly improved. For all polymer blends, a fluorescence peak appeared at a wavelength of 485 nm. These outcomes qualify the PVC/PVP/SrTiO3 polymer blend nanocomposites for optoelectronic applications.

Electro-modulation and surface photovoltage spectroscopy with semi-transparent graphene electrodes

Investigating the fundamental properties of new semiconductor materials and structures requires the use of a wide range of optical spectroscopy techniques. Among them, there are those that exploit the use of electrodes that are semi-transparent to light, a requirement arising from the need to either apply external perturbation to the studied material or sense the effects generated by light excitation. In this work, semi-transparent graphene electrodes were obtained by chemical vapour deposition of the graphene on a copper substrate and transferring these layers to a sapphire substrate. The fabricated electrodes were tested in contactless electroreflectance, soft-contact electroreflectance, and surface photovoltage spectroscopy on III-V epilayers (InP and GaAs) and van der Waals crystals (MoS2 and WSe2), reference industry-standard and emerging semiconductors. The obtained results clearly show that graphene electrodes are suitable for these measurements and have many advantages over the commonly used approaches to ensure transparent conducting layers in optoelectronic devices. On the other hand, compared to indium‑tin oxide, their transparency covers a wide spectral range, including ultraviolet (UV), revealing another important advantage. We also demonstrate that further structuring of the graphene layer enables maximizing the transparency up to the limit imposed by the hosting substrate.

Heating an imitation bubble to focus on fluorescent bacteria

Optical condensation and spectroscopic techniques enable the analysis of a trace amount of dilute biological substances

Multifunctional Folic acid‐coated and Doxorubicin Encapsulated Mesoporous Silica Nanocomposites (FA/DOX@Silica) for Cancer Therapeutics, Bioimaging and invitro Studies

AbstractCancer is a cluster of diseases, which caused by the mutation in cells and it has the potential to cover any part of the body. The whole world is vigorously struggling to find a safe approach to cure the cancer. The classical chemotherapy approach involves the use of chemotherapeutic agents to kill cancer cells. The major disadvantage of therapy is less in vivo stability and negatively affects the healthy cells. Nowadays, the targeted drug delivery techniques has gained lots of interest, because of the efficient drug release at the cancerous sites. Herein, we have synthesized Folic acid (FA) coated and Doxorubicin drug (Dox) encapsulated mesoporous silica nanocomposites (FA/Dox@Silica)for targeted delivery of DOX and bioimaging. Encapsulation of Dox was done to make it more stable in the cell atmosphere and for its controlled release. The coating of FA makes these nanocomposites makes them an vehical for chemically targeted delivey of DOX, as it was already confirmed by several studies that there are folate receptors present over cancer cells and these reseptors are responsive towards the FA Thus these nanocomposites can be easily recognized by the cancer cells and they can efficiently deliver drugs. The shape, size, morphology, crystallinity, porosity, and fictionalizations were analyzed by using several characterization techniques such as DLS, TEM, and FTIR. The drug loading was confirmed qualitatively by using optical spectroscopic techniques. The drug release pattern was studiedfor the 15 days which showed the sustained and regulated release of drug from the mesoporous silica nanocomposites. Cellular uptake was observed by cell staining assay confirmed the fair uptake of nanoparticles.

High current short pulse driver using a high power diode laser for optoacoustic biomedical imaging techniques.

Optoacoustic biomedical imaging combines the high spatial resolution of the ultrasound imaging with the specificity of the optical absorption spectroscopy techniques. It is being used in various scenarios such as anatomical, functional and molecular imaging. Typically light sources for this imaging technique is based on solid state lasers since they can produce high energy short optical pulses. However, they are bulky, expensive and the imaging speed is limited because their low pulse repetition rate. High power diode lasers (HPDLs) are a promising alternative for imaging small volume absorbers as they are compact, affordable and allow high repetition rates. However, HPDLs provide relative low peak optical power compared to solid state lasers. Therefore, imaging systems based on diode lasers require much longer pulse duration resulting in lower in-depth resolution and optoacoustic conversion efficiency. HPDLs need dedicated fast electronics to generate short optical pulses. In this work, we have designed, built and test a pulsed diode laser driver based on RF power MOSFETs, specifically considering the optimization of the current pulse in order to maximize the optical peak power, achieving current pulses of more than 900 A with a duration of 50 ns. We have studied the operation of a low cost HPDL out of the manufacturers datasheet ratings without noticeable degradation at high current (> 250 A) and short pulse duration (< 60 ns). We have obtained an optical peak power of 750 W and a energy per pulse of 31.2 µJ at 40 ns optical pulse duration. The optoacoustic images obtained in this operation regime shown a clear enhancement respect to the ones obtained in standard operation of the HPDL.

Transient THz Emission and Effective Mass Determination in Highly Resistive GaAs Crystals Excited by Femtosecond Optical Pulses

We present comprehensive studies on the emission of broadband, free-space THz transients from several highly resistive GaAs samples excited by femtosecond optical pulses. Our test samples are characterized by different degrees of disorder, ranging from nitrogen-implanted to semi-insulating and annealed semi-insulating GaAs crystals. In our samples, we clearly observed transient THz emissions due to the optical rectification effect, as well as due to the presence of the surface depletion electrical field. Next, we arranged our experimental setup in such way that we could observe directly how the amplitude of surface-emitted THz optical pulses is affected by an applied, in-plane magnetic field. We ascribe this effect to the Lorentz force that additionally accelerates optically excited carriers. The magnetic-field factor η is a linear function of the applied magnetic field and is the largest for an annealed GaAs sample, while it is the lowest for an N-implanted GaAs annealed at the lowest (300 °C) temperature. The latter is directly related to the longest and shortest trapping times, respectively, measured using a femtosecond optical pump-probe spectroscopy technique. The linear dependence of the factor η on the trapping time enabled us to establish that, for all samples, regardless of their crystalline structure, the electron effective mass was equal to 0.059 of the electron mass m0, i.e., it was only about 6% smaller than the generally accepted 0.063m0 value for GaAs with a perfect crystalline structure.

Parametric study of magnetically confined Cu-plasma by using optical emission spectroscopy (OES) and Faraday cup (FC) techniques

A parametric study of magnetically confined Nd:YAG laser induced Cu plasma was performed by using OES and FC techniques at different irradiances and pressures of Ar and Ne at different time delays. Both LIBS and FC analyses revealed that Cu plasma parameters (electron temperature (Te) electron/ion number density (ne/ni) are significantly enhanced in the presence of magnetic field. Without magnetic field under Ar environment, Te varies from 10,801 K to 8026 K, and ne of Cu plasma varies from1.6 × 1018 cm−3 to 0.9 × 1018 cm−3. Whereas, in the presence of magnetic field, these plasma parameters are enhanced from 12,648 K to 8300 K and from 1.6 × 1018 cm−3 to 1.03 × 1018 cm−3 respectively. FC measurements confirm that fluence of electrons and ions is increased in the presence of magnetic field from 2.6 × 1010 cm−2 to 4.2 × 1012 cm−2 and from 7.6 × 1011 cm−2 to 3.7 × 1012 cm−2 respectively. These higher values of Cu plasma parameters are attributed to Joule’s heating and adiabatic compressions after magnetic confinement.

Rare earth effect on laser produced plasma dynamics during pulsed laser deposition of doped cobalt ferrite

The addition of rare earth elements the ferrites can lead to significant changes in structural, magnetic and electric properties of bulk materials and also of thin films deposited by pulsed laser deposition. The present study relies on the analysis of the laser induced plasma of three sets of cobalt ferrite targets doped with various concentrations of RE elements (Dy, Gd, Yb) and proposes a correlation of the derived results with structural investigations of the films obtained during the same experiment. ICCD imaging and space-and time-resolved optical emission spectroscopy techniques were used to obtain information on the dynamics and excitation temperatures of various species found in the laser produced plasmas (LPP). Initial investigations on the global behavior of the LPP revealed that the addition of RE reduced the drift velocities of the formed plasma structures, the lowest ones being observed for the targets doped with the heaviest RE (Yb). Space-and time-resolved spectroscopy measurements applied for all main elements (Fe, Co and RE - both neutral and ionic species) showed a complex dynamic system, with decreased/increased kinetic energies for neutrals/ions at high dopant concentrations, suggesting a possible re-sputtering effect at the films surface. The individual excitation temperatures of the main elements derived from Boltzmann plots increased as the RE content was augmented via radiative collision events due to their larger diameters compared with Co, Fe or O. The spatial distribution of electron temperature can be explained by the charge separation occurring with the addition of RE in the investigated systems.

Computational investigation of hydrogen-induced phonon changes in carbon fiber

Optical vibrational spectroscopy has shown promise as a noninvasive means of monitoring the mechanical properties of carbon fiber (CF), which is increasingly used for industrial and consumer purposes. However, interpretation of optical vibrational spectra for solid materials is inferential, particularly when defects are present. Because inelastic neutron scattering (INS) spectroscopy is not subject to selection rules, the full vibrational spectra can be measured. And, identifying correlations between INS features and tensile properties can assist in the interpretation of spectra from more commonly used optical vibrational spectroscopic techniques, such as Raman and infrared (IR) spectroscopy. Recent INS experiments on high-performance commercial carbon fibers showed features near 900 and 1100 cm−1 in addition to a broad feature near 3000 cm−1 that increased in intensity with decreasing tensile strength. These features were assigned to hydrogen defects. In the present work, we use density functional theory to simulate the INS spectra of several hydrogen defect geometries in graphite as a model for carbon fiber structure units, confirming the experimental assignment of these peaks to hydrogen modes and providing insights into the structure and lattice dynamics of the defects.

Spectrometers in Wonderland: Shrinking, Shrinking, Shrinking

This article gives a brief overview of the major portable techniques: those based on optical spectroscopy techniques, including near-infrared (NIR), mid-infrared (mid-IR), and Raman spectroscopy; mass spectrometry (MS) systems, including high-pressure MS (HPMS), gas chromatography–MS (GC–MS), ion mobility spectrometry (IMS); elemental techniques, such as X-ray fluorescence (XRF) and laser-induced breakdown spectroscopy (LIBS); and emerging miniaturized techniques like nuclear magnetic resonance (NMR). The above are all “conventional” spectroscopic techniques and reduced to a rugged portable format, containing self-contained data systems. They provide specific and actionable information to their operators working with them outside the laboratory—in the field—and these instruments have well-defined value propositions. A recent development is the availability of low cost (&lt;$100) multispectral sensors operating in the visible and NIR regions. This low cost enables the sensors to be embedded into consumer products, such as smart “white goods” appliances, personal care, fitness products, and even “wearables” products. In the future, miniature and portable spectrometers will be ubiquitous—outside the laboratory, and in your home and pocket.

Optical imaging spectroscopy coupled with machine learning for detecting heavy metal of plants: A review.

Heavy metal elements, which inhibit plant development by destroying cell structure and wilting leaves, are easily absorbed by plants and eventually threaten human health via the food chain. Recently, with the increasing precision and refinement of optical instruments, optical imaging spectroscopy has gradually been applied to the detection and reaction of heavy metals in plants due to its in-situ, real-time, and simple operation compared with traditional chemical analysis methods. Moreover, the emergence of machine learning helps improve detection accuracy, making optical imaging spectroscopy comparable to conventional chemical analysis methods in some situations. This review (a): summarizes the progress of advanced optical imaging spectroscopy techniques coupled with artificial neural network algorithms for plant heavy metal detection over ten years from 2012-2022; (b) briefly describes and compares the principles and characteristics of spectroscopy and traditional chemical techniques applied to plants heavy metal detection, and the advantages of artificial neural network techniques including machine learning and deep learning techniques in combination with spectroscopy; (c) proposes the solutions such as coupling with other analytical and detection methods, portability, to address the challenges of unsatisfactory sensitivity of optical imaging spectroscopy and expensive instruments.

Non-Destructive Monitoring of Ripening Process of the Underutilized Fruit Kadam Using Laser-Induced Fluorescence and Confocal Micro Raman Spectroscopy

Underutilized fruits like kadam are bio-reserves of numerous biochemical and minerals and have the potential to be used as food alternatives and supplements to fulfill the needs of malnourished populations. The production of quality fruits needs monitoring throughout the growth and ripening in order to build consumer and industry confidence. The nondestructive optical spectroscopic techniques have immense potential to monitor the growth and ripening indices of the fruits. Hence, this study explores the potential of laser-induced fluorescence and confocal micro Raman spectroscopy for the reliable and cost effective monitoring of growth and ripening of kadam fruits. The analysis of the laser-induced fluorescence measurements reveals that the ripening of the kadam fruits may be monitored by analyzing the fluorescence emission of chlorophyll and carotenoids. The decrease in the intensity of chlorophyll fluorescence accompanied by the increase in the intensity of the carotenoid bands is the characteristic fluorescence signature associated with the ripening of the kadam fruits. Hence, upon the ripening of the fruits, the concentration of chlorophyll decreases considerably with the accumulation of carotenoids. This fact is further complimented by confocal micro Raman measurements, which show that as the fruit ripens, the intensity of carotenoid bands increases dramatically. The observed spectral features may be used by the horticulture scientists and nutritionists to monitor the growth, maturity, and ripening of underutilized fruits like kadam in order to maximize the quality and minimize postharvest losses.