Raman Spectral Measurements Research Articles

Integrating multi-spectral imaging and Raman spectroscopy for in vivo endoscopic assessment of rat intestinal tract

An integrated system for in vivo multi-spectral imaging (MSI) and Raman spectroscopy was developed to understand the external morphology and internal molecular information of biological tissues. The achieved MSI images were reconstructed by eighteen separated images from 400 nm to 760 nm, whose illumination bands were selected with six tri-channel band filters. Based on the spectral analysis algorithms, the spatial distribution patterns of blood volume, blood oxygen content and tissue scatterer volume fraction were visualized. In vivo Raman spectral measurements were executed by inserting specially designed optical probe into instrumental channel of endoscope. By this way, the molecular composition at selected sampling points could be identified with its fingerprint spectral information under the guidance of molecular imaging modality. Therefore, both structural and compositional features of intestinal membrane could be addressed without labeling and continuously. The achieved results testified that our presented methodology reveals insights not easily extracted from either MSI or Raman spectroscopy individually, which brings the enrichment of biological and chemical meanings for future in vivo studies.

Alteration in the Raman spectra of characteristic rock‐forming silicate mixtures due to micrometeorite bombardment

AbstractInnovative techniques are required for the in situ investigation of the surfaces of planetary bodies when landings are planned. Raman spectroscopy turned out as an excellent tool for fast mineralogical analyses on space missions. Contribution from a photoluminescence signal is not unexpected and is likely to be even more pronounced on celestial surfaces with a dilute or absent atmosphere exposed to strong space weathering, for example, micrometeorite bombardment. Such signals were found, for example, in Raman analysis of the probes from sample‐return missions. While photoluminescence is generally considered as an accompanying undesired product in the Raman spectral measurement, our studies show that some analytical information can be derived from this signal, and even more, due to the specific correlation of luminescence intensity with space weathering products. Therefore, we investigate the Raman spectra alteration of characteristic rock‐forming mineral mixtures (olivine, pyroxene and plagioclase) by micrometeorite bombardment, which is simulated by nanosecond‐pulse laser irradiation. The changes in the minerals are strongly dependent on the composition and structure. They range from disappearing changes in the minerals with simple chemistry and structure to complete amorphization of minerals with relatively low melting enthalpy. With Raman spectroscopy, we found out that the photoluminescence signals show resonant or anti‐resonant changes to specific mineral phases and amorphization. Furthermore, ablation‐induced iron nanoparticles of minerals containing Fe are detectable by Raman spectroscopy due to their alteration into iron oxides. Trapped volatiles in the matrices are analysed due to the formation of the compounds containing them. This broad spectrum of results indicating specific change phenomena due to space weathering can be effectively used for in situ Raman analysis in planetary missions.

Abstract 1067: Label free Raman spectroscopy of extracellular vesicles for early stage liquid biopsy cancer detection

Abstract Aim: To improve patient outcomes, there remains a critical need to develop faster, less invasive platforms capable of identifying biomarkers. Multi-omics approaches, while promising, are high in cost and complexity, low throughput, slow, and require large sample volumes, thus are impractical for many stages of clinical care. Raman spectroscopy (RS) addresses many of these needs: it requires little to no sample preparation, is non-destructive, does not need exogenous dyes or labelling agents, and can be performed directly in aqueous solutions. Surface enhanced Raman spectroscopy (SERS) offers further improvements in terms of sensitivity but increases complexity. In this study we carried out comprehensive RS and SERS measurements on a >100-person cohort of blood and saliva from head and neck cancer (HNC) patients and benign controls. Analyses were carried out on whole biofluids, in addition to extracellular vesicles (EVs) isolated from the biofluids to investigate the added value. EVs are emerging biomarkers of interest found in high numbers in circulating biofluids with great promise to increase the specificity of diagnostic platforms. Results: We analyzed a robust clinical dataset of HNC patient saliva and plasma to build a diagnostic model. We found distinct Raman and SERS signatures of metabolites in all cancer samples uniquely present compared to non-cancer controls. Raman spectral measurements fused together for EVs and whole biofluids across saliva and plasma delivered accuracies of >95% using a novel machine learning module based on convolutional neural networks. Our platform features an automated method to isolate EVs amenable to rapid clinical use. Conclusions: The results of this study indicate an exciting step in validating Raman as a robust diagnostic tool revealing that complementary chemical information spread out across biofluids and biomarkers of interest can strongly improve simple, quick Raman based diagnostics of whole biofluids and EVs. Citation Format: Randy P. Carney, Maria Navas-Moreno, Andrew Birkeland. Label free Raman spectroscopy of extracellular vesicles for early stage liquid biopsy cancer detection [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1067.

High pressure Raman study of isobutyramide

Isobutyramide (IBA) has attracted considerable attention due to its expansive prospects for practical applications in the synthesis of drugs, dyes and other organic compounds. Herein we perform the high-pressure studies of IBA crystal by Raman spectral measurements at room temperature from ambient pressure to 30 GPa by using diamond anvil cells (DACs) to gain comprehensive insights into its structure and stability. Raman vibrational modes of IBA crystal at ambient pressure are resolved based on the experimental results and the first-principles theoretical calculations. High-pressure Raman scattering results show the Raman bands splitting, emergence/disappearance of the Raman bands and discontinuous wavenumber shifts at 1, 2 and 10 GPa, which indicate that IBA crystal undergoes three structural phase transitions at corresponding pressure. In addition, softening of the C = O and N–H stretching vibrational modes of IBA with increasing pressure can be interpreted by the reorganization of the hydrogen bond network of IBA molecules due to phase transition.

Preparation of a polyaniline/ZnO-NPs composite for the visible-light-driven hydrogen generation

Compositions of ZnO nanoparticles and polyaniline, in the form of emeraldine salt, were manufactured as thin layers by using the spin-coating method. Then, the effect of polyaniline content on their photoelectrochemical characteristics was studied. Results indicate that all the samples are sensitive to light. Besides, with 0.30% of PANI, the composite sample demonstrates the highest photocurrent density; also, its photocurrent increment starts to increase at a voltage of ⁓ 1.23 V (vs. RHE), which is approximately in accordance with the theoretical potential of water electrolysis. Furthermore, since the rate of electron–hole recombination in this composite sample is the lowest, it possesses the highest photoelectrochemical efficiency. Main findings were analyzed with respect to UV–visible absorption and photoluminescence spectra as well as SEM micrographs of the samples and Raman spectral measurements. Besides, electrochemical impedance spectroscopy analysis was applied to both pure ZnO and the sample with the best response. Effects of drying temperature and layer thickness were also investigated.

Non-invasive biochemical analysis and comparison of atopic dermatitis and psoriasis skin using handheld confocal Raman spectroscopy.

A handheld non-invasive confocal Raman system (CRS) was used to evaluate the differences in skin biochemicals between atopic dermatitis (AD) and psoriasis, which are inflammatory skin conditions. Raman spectral measurements in the fingerprint and high wavenumber region were acquired using a portable in-house CRS system with excitation lasers operating at 671 and 785 nm. It was deduced that relative amount of water decreases in the following sequence of skin: healthy, psoriasis and AD. Moreover, differential trends were observed for the subclasses of ceramides such that ceramide 3 is lower in the lesional AD and psoriasis skin as compared to healthy, while ceramide 2 showed a contrasting trend of decrease in lesional AD and increase in lesional psoriasis as opposed to healthy skin. Amount of cholesterol was significantly higher in lesional psoriasis as compared to lesional AD and healthy skin. These differences can aid in an objective classification of the skin conditions and in the formulation of new disease-specific topical treatments.

Superlattices, Bonding-Antibonding, Fermi Surface Nesting, and Superconductivity

Raman and synchrotron THz absorption spectral measurements on MgB2 provide experimental evidence for electron orbital superlattices. In earlier work, we have detected THz spectra that show superlattice absorption peaks with low wavenumbers, for which spectral density evolves and intensifies after cooling below the superconducting transition temperature for MgB2. In this work, we show how these observations indicate a direct connection to superconducting properties and mechanisms. Bonding–antibonding orbital character is identified in calculated electronic band structures and Fermi surfaces consistent with superlattice structures along the c-axis. DFT calculations show that superlattice folding of reciprocal space generates Brillouin zone boundary reflections, Umklapp processes, and substantially enhances nesting relationships. Tight binding equations are compared with expected charge density waves from nesting relationships and adjusted to explicitly accommodate these linked processes. Systematic analysis of electronic band structures and Fermi surfaces allows for direct identification of Cooper pairing and the superconducting gap, particularly when the k-grid resolution of a calculation is suitably calibrated to structural parameters. Thus, we detail a robust and accurate DFT re-interpretation of BCS superconductivity for MgB2.

Photon-noise: is a single-pixel camera better than point scanning? A signal-to-noise ratio analysis for Hadamard and Cosine positive modulation

In a single-pixel camera, an unknown object is sequentially illuminated by intensity patterns. The total reflected or transmitted intensity is summed in a single-pixel detector from which the object is computationally reconstructed. In the situation where the measurements are limited by photon-noise, it is questionable whether a single-pixel camera performs better or worse than simply scanning the object with a focused intensity spot—a modality known as point raster scanning and employed in many laser scanning systems. Here, we solve this general question and report that positive intensity modulation based on Hadamard or Cosine patterns does not necessarily improve the single-to-noise ratio (SNR) of single-pixel cameras, as compared to point raster scanning (RS). Instead, we show that the SNR is only improved on object pixels at least k times brighter than the object mean signal , where k is a constant that depends on the modulation scheme (modulation matrix, number of detectors, etc). The constant k is derived for several widespread cases and has important consequences on the choice of the optical deign. This fundamental property is demonstrated theoretically, numerically, and is experimentally confirmed in the spatial domain (widefield fluorescence imaging) and in the spectral domain (spontaneous Raman spectral measurements). Finally, we provide user-oriented guidelines that help decide when and how multiplexing under photon-noise should be used instead of point RS.

GaSb band-structure models for electron density determinations from Raman measurements.

We investigate the use of Raman spectroscopy to measure carrier concentrations in GaSb epilayers to aid in the development of this technique for the nondestructive characterization of transport properties in doped semiconductors. The carrier concentration is quantified by modeling the measured coupled optical phonon-free carrier plasmon mode spectra. We employ the Lindhard-Mermin optical susceptibility model with contributions from carriers in the two lowest GaSb conduction-band minima, the and minima. Furthermore, we evaluate three conduction-band models: (1) both minima parabolic and isotropic, (2) the minimum non-parabolic and isotropic and the minima parabolic and isotropic, and (3) the minimum non-parabolic and isotropic and the minima parabolic and ellipsoidal. For a given epilayer, the carrier concentration determined from the spectral simulations was consistently higher for the ellipsoidal minima model than the other two models. To evaluate the conduction-band models, we calculated the to electron mobility ratio necessary for the electron concentrations from the Raman spectral measurements to reproduce those from the Hall effect measurements. We found that the model with the ellipsoidal minima agreed best with reported carrier-dependent mobility-ratio values. Hence, employing isotropic minima in GaSb conduction-band models, a common assumption when describing the GaSb conduction band, likely results in an underestimation of carrier concentration at room temperature and higher doping levels. This observation could have implications for Raman spectral modeling and any investigation involving the GaSb conduction band, e.g., modeling electrical measurements or calculating electron mobility.

Real-time in vivo cancer staging of nasopharyngeal carcinoma patients with rapid fiberoptic Raman endoscopy

Cancer staging is important to guide treatment and for prognostication. This work aims to demonstrate the ability of rapid fiberoptic Raman endoscopy for real-time in vivo cancer staging of nasopharyngeal cancer (NPC) patients. We interrogate 278 tissue sites on the primary NPC with different cancer stages from 61 NPC patients and 50 healthy volunteers using rapid fiberoptic Raman endoscopy examination. Distinct Raman spectral differences of NPC at different cancer stages are observed through simultaneous fingerprint and high-wavenumber (FP/HW) Raman spectral measurements, reflecting the biomolecular differences of NPC tumor across various cancer stages. Raman staging model is established based on in vivo FP/HW tissue Raman spectra together with partial-least-squares linear-discriminant-analysis (PLS-LDA) and leave-one-tissue-site-out cross-validation (LOOCV). In vivo FP/HW Raman endoscopy provides an overall diagnostic accuracy of 92.81% for identifying different stages of NPC (i.e., NPC stage I&II and NPC stage III&IV) from normal nasopharynx. Specifically, the diagnostic sensitivity of 91.18% is obtained for identifying NPC stage I& II; and the sensitivity of 93.04% is achieved for classifying NPC stage III&IV from normal tissue. The key tissue biomolecular variations responsible for different NPC stages have been identified using biomolecular Raman modeling developed based on non-negative linear regression. The essential biomolecules (chondroitin sulfate, glucose, hemoglobin, oleic acid and triolein) are uncovered from the Raman spectra of NPC tissues through biomolecular modeling with significant variations (p < 0.05) between early-stage NPC (stage I and stage II) and late-stage NPC patients (stage III and stage IV). Our pivotal work demonstrates for the first time that fiberoptic Raman endoscopy is a robust analytical tool for real-time in vivo NPC staging in clinical settings.

Raman spectral analysis of microbial pigment compositions in vegetative cells and heterocysts of multicellular cyanobacterium

The one-dimensional multicellular cyanobacterium, Anabaena sp. PCC 7120, exhibits a simple topology consisting of two types of cells under the nitrogen-depleted conditions. Although the differentiated (heterocyst) and undifferentiated cells (vegetative cells) were distinguished by their cellular shapes, we found that their internal states, that is, microbial pigment compositions, were distinguished by using a Raman microscope. Almost of Raman bands of the cellular components were assigned to vibrations of the pigments; chlorophyll a, β-carotene, phycocyanin, and allophycocyanin. We found that the Raman spectral measurement can detect the decomposition of both phycocyanin and allophycocyanin, which are components of the light-harvesting phycobilisome complex in the photosystem II. We observed that the Raman bands of phycocyanin and allophycocyanin exhibited more remarkable decrease in the heterocysts when compared to those of chlorophyll a and β-carotene. This result indicated the prior decomposition of phycobilisome in the heterocysts. We show that the Raman measurement is useful to detect the change of pigment composition in the cell differentiation.

Feedback-based wavefront shaping for weak light with lock-in beat frequency detection.

Feedback-based wavefront shaping is a promising and versatile technique for enhancing the contrast of a target signal through highly scattering media. However, this technique can fail for low optical signals such as fluorescence and Raman signals or in a reflection setup because the trend in weak feedback signals can be easily overwhelmed by noise. To address this challenge, we develop a technique based on a single acousto-optic deflector (AOD) to create a signal with a selected beat frequency from optical signals that can serve as feedback, in which the phase distribution of various radio frequency components of the driving signal for the AOD is optimized for wavefront shaping. By shifting incident light frequency with the AOD, the feedback signal at a selected beat frequency can be measured with a high signal-to-noise ratio (SNR) by a lock-in amplifier, thus enabling the enhancement of weak target signals through highly scattering media. It is found that the method of lock-in beat frequency detection can significantly improve fluorescence imaging and Raman spectral measurements in a reflection setup, and thus could be potentially used for in vivo measurements.

Multimodal Approach of Optical Coherence Tomography and Raman Spectroscopy Can Improve Differentiating Benign and Malignant Skin Tumors in Animal Patients.

Simple SummarySkin and subcutaneous tumors are among the most frequent neoplasms in dogs and cats. We studied 51 samples of canine and feline skin, lipomas, soft tissue sarcomas, and mast cell tumors using a multimodal approach based on optical coherence tomography and Raman spectroscopy. A supervised machine learning algorithm detected malignant tumors with the sensitivity and specificity of 94% and 98%, respectively. The proposed multimodal algorithm is a novel approach in veterinary oncology that can outperform the existing clinical methods such as the fine-needle aspiration method.As in humans, cancer is one of the leading causes of companion animal mortality. Up to 30% of all canine and feline neoplasms appear on the skin or directly under it. There are only a few available studies that have investigated pet tumors by biophotonics techniques. In this study, we acquired 1115 optical coherence tomography (OCT) images of canine and feline skin, lipomas, soft tissue sarcomas, and mast cell tumors ex vivo, which were subsequently used for automated machine vision analysis. The OCT images were analyzed using a scanning window with a size of 53 × 53 μm. The distributions of the standard deviation, mean, range, and coefficient of variation values were acquired for each image. These distributions were characterized by their mean, standard deviation, and median values, resulting in 12 parameters in total. Additionally, 1002 Raman spectral measurements were made on the same samples, and features were generated by integrating the intensity of the most prominent peaks. Linear discriminant analysis (LDA) was used for sample classification, and sensitivities/specificities were acquired by leave-one-out cross-validation. Three datasets were analyzed—OCT, Raman, and combined. The combined OCT and Raman data enabled the best sample differentiation with the sensitivities of 0.968, 1, and 0.939 and specificities of 0.956, 1, and 0.977 for skin, lipomas, and malignant tumors, respectively. Based on these results, we concluded that the proposed multimodal approach, combining Raman and OCT data, can accurately distinguish between malignant and benign tissues.

Spatiotemporal-Resolved Hyperspectral Raman Imaging of Plasmon-Assisted Reactions at Single Hotspots.

Raman spectroscopy facilitates the study of reacting molecules on single nanomaterials. In recent years, the temporal resolution of Raman spectral measurement has been remarkably reduced to the millisecond level. However, the classic scan-based imaging mode limits the application in the dynamical study of reactions at multiple nanostructures. In this paper, we propose a spatiotemporal-resolved Raman spectroscopy (STRS) technology to achieve fast (∼40 ms) and high spatial resolution (∼300 nm) hyperspectral Raman imaging of single nanostructures. With benefits of the outstanding electromagnetic field enhancement factor by surface plasmon resonance (∼1012) and the snapshot hyperspectral imaging strategy, we demonstrate the observation of stepwise Raman signals from single-particle plasmon-assisted reactions. Results reveal that the reaction kinetics is strongly affected by not only the surface plasmon-polariton generation but also the density of Raman molecules. In consideration of the spatiotemporal resolving capability of STRS, we anticipate that it provides a potential platform for further extending the application of Raman spectroscopy methods in the dynamic study of 1D or 2D nanostructures.

Atrial fibrillation designation with micro-Raman spectroscopy and scanning acoustic microscope

Atrial fibrillation (AF) is diagnosed with the electrocardiogram, which is the gold standard in clinics. However, sufficient arrhythmia monitoring takes a long time, and many of the tests are made in only a few seconds, which can lead arrhythmia to be missed. Here, we propose a combined method to detect the effects of AF on atrial tissue. We characterize tissues obtained from patients with or without AF by scanning acoustic microscopy (SAM) and by Raman spectroscopy (RS) to construct a mechano-chemical profile. We classify the Raman spectral measurements of the tissue samples with an unsupervised clustering method, k-means and compare their chemical properties. Besides, we utilize scanning acoustic microscopy to compare and determine differences in acoustic impedance maps of the groups. We compared the clinical outcomes with our findings using a neural network classification for Raman measurements and ANOVA for SAM measurements. Consequently, we show that the stiffness profiles of the tissues, corresponding to the patients with chronic AF, without AF or who experienced postoperative AF, are in agreement with the lipid-collagen profiles obtained by the Raman spectral characterization.

Optical and magnetic properties of fluoride-doped CeO2 obtained by an oxidative insertion method

• CeO 2 : F sample is synthesized using molten flux promoted oxidative insertion method. • PXRD and Raman spectral measurements confirmed the fluorite structure of CeO 2 :F. • Besides Ce and O, EDX analysis also revealed the presence of 18 at. % of fluoride. • PL and magnetic studies revealed a lower concentration of O vacancies in CeO 2 :F. • The F-doped sample had a higher concentration of Ce 3+ in CeO 2 :F. In the present study, we generated a fluoride-doped CeO 2 sample through the molten hydroxide flux promoted oxidative insertion approach using CeF 3 as the precursor. We analyzed the results and compared them with pure CeO 2 prepared by the same approach starting from Ce(NO 3 ) 3 . High-resolution powder X-ray diffraction, FTIR, and Raman spectral measurements confirmed both samples’ fluorite structure. The CeO 2 resulted from the oxidative flux treatment of CeF 3 had 18 at.% of fluoride ion-doped in it. The optical band gap narrowed marginally from 2.98 to 2.88 eV upon fluoride doping in CeO 2 . The blue emission intensity decreased with fluoride doping, indicating a reduction in oxygen vacancies compared to undoped CeO 2 . F-doped CeO 2 showed ferromagnetic behavior with magnetization, H c, and M r values higher than the undoped sample. A higher concentration of Ce 3+ and a lower concentration of oxygen vacancies were the consequences of fluoride doping in CeO 2 by this synthetic method.

Raman spectroscopic study of benign and malignant ovarian tissues

Ovarian cancer is one of the most common female tumors all over the world, and its mortality rate ranks first among gynecological malignancies. A progressive assessment, diagnosis and remedy are significant for the proper management of the disease process. In this paper, a prompt, non-invasive and highly effective screening test for ovarian cancer was developed based on the Raman spectroscopy (RS) data of fresh ovarian tissues. Raman spectral measurements were performed on fresh ovarian tissue samples from 17 ovarian cancer patients and 14 benign ovarian tumors. We preliminarily identified the Raman peaks in the measured ovarian tissue spectra and summarized their respective characteristic peaks, indicating that specific biomolecules changed among different groups, and their differences were analyzed. The conclusions suggested that the position of the characteristic peaks of Raman spectrum of the ovarian cancer tissues and benign ovarian tissues were different. The relative intensity of ovarian cancer tissue was higher than that of benign ovarian tissue at the 1004, 1155, 1446 cm−1 with phenylalanine, protein and lipids as characteristic peaks, and the difference were significant (P < 0.05). This exploratory work demonstrates that RS may be used as a detection method for screening benign and malignant ovarian tumors.

Microstructures and mechanical properties of Zr-based metallic glass ablated by nanosecond pulsed laser in various gas atmospheres

The surface with micro-convex prepared by laser ablation is beneficial to improving the functional properties of metallic glasses (MGs). However, accompanied by the formation of micro-convex, surface hardness of the ablated area generally decreases due to the softening effect caused by laser thermal shock. Previous studies have shown that the mechanical properties of laser-ablated MG surface are significantly different when using different gas atmospheres. In this study, a comparative investigation was performed to analyze the influence of gas atmosphere (i.e. argon, nitrogen, and air) on the formation of micro-convex as well as its surface characteristics and mechanical properties. Experimental results showed that the atmosphere type did not affect the formation of micro-convex, but significantly affected the surface morphology and element composition of the laser-ablated area. The element analysis and Raman spectral measurements indicated that laser ablation in nitrogen or air atmosphere resulted in local nitridation or oxidation. The results of nanoindentation tests demonstrated that laser ablation in nitrogen or air atmosphere also resulted in surface hardness inhomogeneity, i.e., softening and hardening effects coexist in the ablated area, which could be attributed to the combined influence of laser thermal shock, the introduction of secondary phase as well as laser ablation induced loose structure.

Detection of the mineral constituents in human renal calculi by vibrational spectroscopic analysis combined with allied techniques Powder XRD, TGA, SEM, IR imaging and TXRF

Detection of the mineral constituents in a batch of 310 samples of human urinary calculi (kidney stones-235 and bladder stones-75) combined with a semi-quantitative analysis has been presented on the basis of Fourier Transform based IR and Raman spectral measurements. Some of the observed characteristic IR and Raman bands have been proposed as ‘Marker Bands’ for the most reliable identification of the constituents. A detailed vibrational spectral analysis combined with a DFT level calculation for the functional groups in Calcium Oxalate Monohydrate (COM), Magnesium Ammonium Phosphate Hexahydrate (MAPH), Calcium Hydrogen Phosphate Dihydrate (CHPD), Penta-Calcium Hydroxy-Triphosphate (PCHT) and Uric Acid (UA) has been proposed. It has been shown that the identified mineral constituents as major or minor components can be deduced from the application of Lambert-Beer law of radiation absorption and results are in agreement with quantitative Spectral Data base. This simple method has the potential to be integrated into the management of Urolithiasis, a process of forming renal calculi in the kidney, bladder and/or urethra. Employment of powder XRD, TGA, SEM, TXRF and IR Imaging techniques has provided additional support for the proposed foolproof identification of the mineral constituents. Among the mineral constituents, Calcium Oxalate Monohydrate, Calcium Oxalate Dihydrate or their mixture account for 85% of the total number of samples; the remaining 15% and 5% samples contain Phosphate and Uric acid stones respectively.

Investigation of the TeO2/GeO2 Ratio on the Spectroscopic Properties of Eu3+-Doped Oxide Glasses for Optical Fiber Application.

This study presented an analysis of the TeO2/GeO2 molar ratio in an oxide glass system. A family of melt-quenched glasses with the range of 0–35 mol% of GeO2 has been characterized by using DSC, Raman, MIR, refractive index, PLE, PL spectra, and time-resolved spectral measurements. The increase in the content of germanium oxide caused an increase in the transition temperature but a decrease in the refractive index. The photoluminescence spectra of europium ions were examined under the excitation of 465 nm, corresponding to 7F0 → 5D2 transition. The PSB (phonon sidebands) analysis was carried out to determine the phonon energy of the glass hosts. It was reported that the red (5D0 → 7F2) to orange (5D0 → 7F1) fluorescence intensity ratio for Eu3+ ions decreased from 4.49 (Te0Ge) to 3.33 (Te15Ge) and showed a constant increase from 4.58 (Te20Ge) to 4.88 (Te35Ge). These optical features were explained in structural studies, especially changes in the coordination of [4]Ge to [6]Ge. The most extended lifetime was reported for the Eu3+ doped glass with the highest content of GeO2. This glass was successfully used for the drawing of optical fiber.