Research

Jump to: Review

11 pages, 5175 KiB

Open AccessArticle

Selective Laser Spectroscopy of the Bixbyite-Type Yttrium Scandate Doped by Rare-Earth Ions

by Elena Dobretsova, Olimkhon Alimov, Sergey Rusanov, Vitaly Kashin and Vladimir Tsvetkov

Materials 2023, 16(21), 6829; https://doi.org/10.3390/ma16216829 - 24 Oct 2023

Viewed by 881

Yttrium scandate crystals doped by Nd³⁺ and Tm³⁺ ions have been successfully grown in the form of fibers using the laser-heated pedestal growth (LHPG) technique. The selective laser spectroscopy methods have identified and distinguished three distinct types of optically active centers [...] Read more.

Yttrium scandate crystals doped by Nd³⁺ and Tm³⁺ ions have been successfully grown in the form of fibers using the laser-heated pedestal growth (LHPG) technique. The selective laser spectroscopy methods have identified and distinguished three distinct types of optically active centers associated with Nd³⁺ and Tm³⁺ ions. The substitution of Y³⁺ and Sc³⁺ for rare-earth ions in the C₂ structural site leads to the formation of two distinct basic long-time centers. In Nd³⁺:YScO₃, another type of center (a short-lifetime one) is formed known as the Nd³⁺–Nd³⁺ aggregate pair. This center arises from the substitution of Y³⁺ or Sc³⁺ for Nd³⁺ cation in the adjacent MO₆ polyhedra that share an edge. In Tm³⁺:YScO₃, the third optical center is formed as a result of the substitution of Y³⁺ or Sc³⁺ for Tm³⁺ in the MO₆ octahedra with the C_3i site symmetry. The fluorescence decay lifetimes of Nd³⁺ and Tm³⁺ ions in the YScO₃ crystal structure have been accurately measured and estimated. A Stark level diagram illustrating the splitting of ⁴F_3/2, ⁴I_11/2, and ⁴I_9/2 multiplets of Nd³⁺ ions has been constructed to show features of the active optical centers with the C₂ site symmetry. Full article

(This article belongs to the Special Issue Feature Paper in Optical and Photonic Materials)

► Show Figures

Figure 1

13 pages, 4429 KiB

Open AccessEditor’s ChoiceArticle

Nonlinear Optical Properties of Zn(II) Porphyrin, Graphene Nanoplates, and Ferrocene Hybrid Materials

by Francesca Limosani, Francesca Tessore, Alessandra Forni, Angelo Lembo, Gabriele Di Carlo, Cecilia Albanese, Stefano Bellucci and Pietro Tagliatesta

Materials 2023, 16(15), 5427; https://doi.org/10.3390/ma16155427 - 02 Aug 2023

Viewed by 846

Abstract

Following some previous work by some of us on the second order nonlinear optical (NLO) properties of Zn(II) meso-tetraphenylporphyrin (ZnP), fullerene, and ferrocene (Fc) diads and triads, in the present research, we explore the NLO response of some new hybrids with two-dimensional [...] Read more.

Following some previous work by some of us on the second order nonlinear optical (NLO) properties of Zn(II) meso-tetraphenylporphyrin (ZnP), fullerene, and ferrocene (Fc) diads and triads, in the present research, we explore the NLO response of some new hybrids with two-dimensional graphene nanoplates (GNP) instead of a zero-dimensional fullerene moiety as the acceptor unit. The experimental data, collected by Electric Field Induced Second Harmonic generation (EFISH) technique in CH₂Cl₂ solution with a 1907 nm incident wavelength, combined with Coupled-Perturbed (CP) and Finite Field (FF) Density Functional Theory (DFT) calculations, show a strongly enhanced contribution of the cubic electronic term γ(−2ω; ω, ω, 0), due to the extended π-conjugation of the carbonaceous acceptor moiety. Full article

(This article belongs to the Special Issue Feature Paper in Optical and Photonic Materials)

► Show Figures

Figure 1

15 pages, 4307 KiB

Open AccessArticle

Flexible Substrate of Cellulose Fiber/Structured Plasmonic Silver Nanoparticles Applied for Label-Free SERS Detection of Malathion

by Kseniya V. Serebrennikova, Nadezhda S. Komova, Arseniy V. Aybush, Anatoly V. Zherdev and Boris B. Dzantiev

Materials 2023, 16(4), 1475; https://doi.org/10.3390/ma16041475 - 09 Feb 2023

Cited by 3 | Viewed by 1557

Abstract

Surface-enhanced Raman scattering (SERS) is considered an efficient technique providing high sensitivity and fingerprint specificity for the detection of pesticide residues. Recent developments in SERS-based detection aim to create flexible plasmonic substrates that meet the requirements for non-destructive analysis of contaminants on curved [...] Read more.

Surface-enhanced Raman scattering (SERS) is considered an efficient technique providing high sensitivity and fingerprint specificity for the detection of pesticide residues. Recent developments in SERS-based detection aim to create flexible plasmonic substrates that meet the requirements for non-destructive analysis of contaminants on curved surfaces by simply wrapping or wiping. Herein, we reported a flexible SERS substrate based on cellulose fiber (CF) modified with silver nanostructures (AgNS). A silver film was fabricated on the membrane surface with an in situ silver mirror reaction leading to the formation of a AgNS–CF substrate. Then, the substrate was decorated through in situ synthesis of raspberry-like silver nanostructures (rAgNS). The SERS performance of the prepared substrate was tested using 4-mercaptobenzoic acid (4-MBA) as a Raman probe and compared with that of the CF-based plasmonic substrates. The sensitivity of the rAgNS/AgNS–CF substrate was evaluated by determining the detection limit of 4-MBA and an analytical enhancement factor, which were 10 nM and ~10⁷, respectively. Further, the proposed flexible rAgNS/AgNS–CF substrate was applied for SERS detection of malathion. The detection limit for malathion reached 0.15 mg/L, which meets the requirements about its maximum residue level in food. Thus, the characteristics of the rAgNS/AgNS–CF substrate demonstrate the potential of its application as a label-free and ready-to-use sensing platform for the SERS detection of trace hazardous substances. Full article

(This article belongs to the Special Issue Feature Paper in Optical and Photonic Materials)

► Show Figures

Figure 1

12 pages, 4188 KiB

Open AccessArticle

Pressure Evolution of Ultrafast Photocarrier Dynamics and Electron–Phonon Coupling in FeTe_0.5Se_0.5

by Muyun Li, Yan Zhou, Kai Zhang, Guangyong Xu, Genda Gu, Fuhai Su and Xiaojia Chen

Materials 2022, 15(23), 8467; https://doi.org/10.3390/ma15238467 - 28 Nov 2022

Viewed by 1339

Abstract

Understanding the coupling between electrons and phonons in iron chalcogenides FeTe

_{x}

Se

_{1 - x}

has remained a critical but arduous project in recent decades. The direct observation of the electron–phonon coupling effect through electron dynamics and vibrational properties has been lacking. [...] Read more.

Understanding the coupling between electrons and phonons in iron chalcogenides FeTe

_{x}

Se

_{1 - x}

has remained a critical but arduous project in recent decades. The direct observation of the electron–phonon coupling effect through electron dynamics and vibrational properties has been lacking. Here, we report the first pressure-dependent ultrafast photocarrier dynamics and Raman scattering studies on an iron chalcogenide FeTe

_{0.5}

Se

_{0.5}

to explore the interaction between electrons and phonons in this unconventional superconductor. The lifetime of the excited electrons evidently decreases as the pressure increases from 0 to 2.2 GPa, and then increases with further compression. The vibrational properties of the

A_{1 g}

phonon mode exhibit similar behavior, with a pronounced frequency reduction appearing at approximately 2.3 GPa. The dual evidence reveals the enhanced electron–phonon coupling strength with pressure in FeTe

_{0.5}

Se

_{0.5}

. Our results give an insight into the role of the electron–phonon coupling effect in iron-based superconductors. Full article

(This article belongs to the Special Issue Feature Paper in Optical and Photonic Materials)

► Show Figures

Figure 1

10 pages, 1784 KiB

Open AccessEditor’s ChoiceArticle

Application of Genetically Encoded Photoconvertible Protein SAASoti for the Study of Enzyme Activity in a Single Live Cell by Fluorescence Correlation Microscopy

by Ilya D. Solovyev, Liliya G. Maloshenok and Alexander P. Savitsky

Materials 2022, 15(14), 4962; https://doi.org/10.3390/ma15144962 - 16 Jul 2022

Cited by 2 | Viewed by 1376

Abstract

Fluorescent Correlation Spectroscopy (FCS) allows us to determine interactions of labeled proteins or changes in the oligomeric state. The FCS method needs a low amount of fluorescent dye, near nanomolar concentrations. To control the amount of fluorescent dye, we used new photoconvertible FP [...] Read more.

Fluorescent Correlation Spectroscopy (FCS) allows us to determine interactions of labeled proteins or changes in the oligomeric state. The FCS method needs a low amount of fluorescent dye, near nanomolar concentrations. To control the amount of fluorescent dye, we used new photoconvertible FP SAASoti. This work is devoted to the proof of principle of using photoconvertible proteins to measure caspase enzymatic activity in a single live cell. The advantage of this approach is that partial photoconversion of the FP makes FCS measurements possible when studying enzymatic reactions. To investigate the process, in vivo we used HeLa cell line expressing the engineered FRET sensor, SAASoti-23-KFP. This FRET sensor has a cleavable (DEVD) sequence in the linker between two FPs for the detection of one of the key enzymes of apoptosis, caspase-3. Caspase-3 activity was detected by registering the increase in the fluorescent lifetimes of the sensor, whereas the diffusion coefficient of SAASoti decreased. This can be explained by an increase in the total cell viscosity during apoptosis. We can suppose that in the moment of detectible caspase-3 activity, cell structure already has crucial changes in viscosity. Full article

(This article belongs to the Special Issue Feature Paper in Optical and Photonic Materials)

► Show Figures

Figure 1

15 pages, 976 KiB

Open AccessEditor’s ChoiceArticle

Deep Learning for Type 1 Diabetes Mellitus Diagnosis Using Infrared Quantum Cascade Laser Spectroscopy

by Igor Fufurin, Pavel Berezhanskiy, Igor Golyak, Dmitriy Anfimov, Elizaveta Kareva, Anastasiya Scherbakova, Pavel Demkin, Olga Nebritova and Andrey Morozov

Materials 2022, 15(9), 2984; https://doi.org/10.3390/ma15092984 - 20 Apr 2022

Cited by 10 | Viewed by 2364

Abstract

An estimated 10.5% of the world’s population aged 20–79 years are currently living with diabetes in 2021. An urgent task is to develop a non-invasive express-diagnostics of diabetes with high accuracy. Type 1 diabetes mellitus (T1DM) diagnostic method based on infrared laser spectroscopy [...] Read more.

An estimated 10.5% of the world’s population aged 20–79 years are currently living with diabetes in 2021. An urgent task is to develop a non-invasive express-diagnostics of diabetes with high accuracy. Type 1 diabetes mellitus (T1DM) diagnostic method based on infrared laser spectroscopy of human exhaled breath is described. A quantum cascade laser emitting in a pulsed mode with a peak power of up to 150 mW in the spectral range of 5.3–12.8 μm and Herriot multipass gas cell with an optical path length of 76 m were used. We propose a method for collecting and drying an exhaled human air sample and have measured 1200 infrared exhaled breath spectra from 60 healthy volunteers (the control group) and 60 volunteers with confirmed T1DM (the target group). A 1-D convolutional neural network for the classification of healthy and T1DM volunteers with an accuracy of 99.7%, recall 99.6% and AUC score 99.9% was used. The demonstrated results require clarification on a larger dataset and series of clinical studies and, further, the method can be implemented in routine medical practice. Full article

(This article belongs to the Special Issue Feature Paper in Optical and Photonic Materials)

► Show Figures

Figure 1

17 pages, 12742 KiB

Open AccessEditor’s ChoiceArticle

Optical Coherence Elastography as a Tool for Studying Deformations in Biomaterials: Spatially-Resolved Osmotic Strain Dynamics in Cartilaginous Samples

by Yulia Alexandrovskaya, Olga Baum, Alexander Sovetsky, Alexander Matveyev, Lev Matveev, Emil Sobol and Vladimir Zaitsev

Materials 2022, 15(3), 904; https://doi.org/10.3390/ma15030904 - 25 Jan 2022

Cited by 9 | Viewed by 2252

Abstract

This paper presents a recently developed variant of phase-resolved Optical Coherence Elastography (OCE) enabling non-contact visualization of transient local strains of various origins in biological tissues and other materials. In this work, we demonstrate the possibilities of this new technique for studying dynamics [...] Read more.

This paper presents a recently developed variant of phase-resolved Optical Coherence Elastography (OCE) enabling non-contact visualization of transient local strains of various origins in biological tissues and other materials. In this work, we demonstrate the possibilities of this new technique for studying dynamics of osmotically-induced strains in cartilaginous tissue impregnated with optical clearing agents (OCA). For poroelastic water-containing biological tissues, application of non-isotonic OCAs, various contrast additives, as well as drug solutions administration, may excite transient spatially-inhomogeneous strain fields of high magnitude in the tissue bulk, initiating mechanical and structural alterations. The range of the strain reliably observed by OCE varied from ±10⁻³ to ±0.4 for diluted and pure glycerol, correspondingly. The OCE-technique used made it possible to reveal previously inaccessible details of the complex spatio-temporal evolution of alternating-sign osmotic strains at the initial stages of agent diffusion. Qualitatively different effects produced by particular hydrophilic OCAs, such as glycerol and iohexol, are discussed, as well as concentration-dependent differences. Overall, the work demonstrates the unique abilities of the new OCE-modality in providing a deeper insight in real-time kinetics of osmotically-induced strains relevant to a broad range of biomedical applications. Full article

(This article belongs to the Special Issue Feature Paper in Optical and Photonic Materials)

► Show Figures

Figure 1

13 pages, 2156 KiB

Open AccessEditor’s ChoiceArticle

Single-Fiber Diffuse Reflectance Spectroscopy and Spatial Frequency Domain Imaging in Surgery Guidance: A Study on Optical Phantoms

by Polina S. Tseregorodtseva, Kirill E. Buiankin, Boris P. Yakimov, Armais A. Kamalov, Gleb S. Budylin and Evgeny A. Shirshin

Materials 2021, 14(24), 7502; https://doi.org/10.3390/ma14247502 - 07 Dec 2021

Cited by 4 | Viewed by 2517

Abstract

Diffuse reflectance spectroscopy (DRS) and imaging are increasingly being used in surgical guidance for tumor margin detection during endoscopic operations. However, the accuracy of the boundary detection with optical techniques may depend on the acquisition parameters, and its evaluation is in high demand. [...] Read more.

Diffuse reflectance spectroscopy (DRS) and imaging are increasingly being used in surgical guidance for tumor margin detection during endoscopic operations. However, the accuracy of the boundary detection with optical techniques may depend on the acquisition parameters, and its evaluation is in high demand. In this work, using optical phantoms with homogeneous and heterogeneous distribution of chromophores mimicking normal and pathological bladder tissues, the accuracy of tumor margin detection using single-fiber diffuse reflectance spectroscopy and spatial frequency domain imaging was evaluated. We also showed how the diffuse reflectance response obtained at different spatial frequencies with the spatial frequency domain imaging technique could be used not only to quantitatively map absorption and scattering coefficients of normal tissues and tumor-like heterogeneities but also to estimate the tumor depth localization. The demonstrated results could be helpful for proper analysis of the DRS data measured in vivo and for translation of optical techniques for tumor margin detection to clinics. Full article

(This article belongs to the Special Issue Feature Paper in Optical and Photonic Materials)

► Show Figures

Figure 1

11 pages, 16855 KiB

Open AccessArticle

Ultrafast Third-Order Nonlinear Optical Response Excited by fs Laser Pulses at 1550 nm in GaN Crystals

by Adrian Petris, Petronela Gheorghe, Tudor Braniste and Ion Tiginyanu

Materials 2021, 14(12), 3194; https://doi.org/10.3390/ma14123194 - 10 Jun 2021

Cited by 5 | Viewed by 2364

Abstract

The ultrafast third-order optical nonlinearity of c-plane GaN crystal, excited by ultrashort (fs) high-repetition-rate laser pulses at 1550 nm, wavelength important for optical communications, is investigated for the first time by optical third-harmonic generation in non-phase-matching conditions. As the thermo-optic effect that can [...] Read more.

The ultrafast third-order optical nonlinearity of c-plane GaN crystal, excited by ultrashort (fs) high-repetition-rate laser pulses at 1550 nm, wavelength important for optical communications, is investigated for the first time by optical third-harmonic generation in non-phase-matching conditions. As the thermo-optic effect that can arise in the sample by cumulative thermal effects induced by high-repetition-rate laser pulses cannot be responsible for the third-harmonic generation, the ultrafast nonlinear optical effect of solely electronic origin is the only one involved in this process. The third-order nonlinear optical susceptibility of GaN crystal responsible for the third-harmonic generation process, an important indicative parameter for the potential use of this material in ultrafast photonic functionalities, is determined. Full article

(This article belongs to the Special Issue Feature Paper in Optical and Photonic Materials)

► Show Figures

Figure 1

Review

Jump to: Research

17 pages, 2072 KiB

Open AccessReview

Daylight Photoactive TiO₂ Sol-Gel Nanoparticles: Sustainable Environmental Contribution

by Daniel Alves Barcelos and Maria Clara Gonçalves

Materials 2023, 16(7), 2731; https://doi.org/10.3390/ma16072731 - 29 Mar 2023

Cited by 3 | Viewed by 1612

Abstract

Visible-light-photoactive titania micro- or nanoparticles excel in a wide range of industrial areas, particularly in environmental remediation. The sol–gel methodology is one pivotal technique which has been successfully used to synthesize either crystalline and amorphous TiO₂ micro- and nanoparticles due to its [...] Read more.

Visible-light-photoactive titania micro- or nanoparticles excel in a wide range of industrial areas, particularly in environmental remediation. The sol–gel methodology is one pivotal technique which has been successfully used to synthesize either crystalline and amorphous TiO₂ micro- and nanoparticles due to its outstanding chemical simplicity and versatility, along with the green chemistry approach. This short review aims to collect and discuss the most recent developments in visible-light-photoactive titania-based nanoparticles in the environmental remediation area. Titania co-doping, titania composite design, and, recently, amorphous networks have been the most used strategies to address this goal. Finally, a prediction regarding the future of these fields is given. Full article

(This article belongs to the Special Issue Feature Paper in Optical and Photonic Materials)

► Show Figures

Figure 1

34 pages, 6077 KiB

Open AccessEditor’s ChoiceReview

Magnetite Nanoparticles: Synthesis and Applications in Optics and Nanophotonics

by Nataliia Dudchenko, Shweta Pawar, Ilana Perelshtein and Dror Fixler

Materials 2022, 15(7), 2601; https://doi.org/10.3390/ma15072601 - 01 Apr 2022

Cited by 27 | Viewed by 8546

Abstract

Magnetite nanoparticles with different surface coverages are of great interest for many applications due to their intrinsic magnetic properties, nanometer size, and definite surface morphology. Magnetite nanoparticles are widely used for different medical-biological applications while their usage in optics is not as widespread. [...] Read more.

Magnetite nanoparticles with different surface coverages are of great interest for many applications due to their intrinsic magnetic properties, nanometer size, and definite surface morphology. Magnetite nanoparticles are widely used for different medical-biological applications while their usage in optics is not as widespread. In recent years, nanomagnetite suspensions, so-called magnetic ferrofluids, are applied in optics due to their magneto-optical properties. This review gives an overview of nanomagnetite synthesis and its properties. In addition, the preparation and application of magnetic nanofluids in optics, nanophotonics, and magnetic imaging are described. Full article

(This article belongs to the Special Issue Feature Paper in Optical and Photonic Materials)

► Show Figures

Figure 1

39 pages, 72409 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Photothermal and Photodynamic Therapy of Tumors with Plasmonic Nanoparticles: Challenges and Prospects

by Alla B. Bucharskaya, Nikolai G. Khlebtsov, Boris N. Khlebtsov, Galina N. Maslyakova, Nikita A. Navolokin, Vadim D. Genin, Elina A. Genina and Valery V. Tuchin

Materials 2022, 15(4), 1606; https://doi.org/10.3390/ma15041606 - 21 Feb 2022

Cited by 30 | Viewed by 4932

Abstract

Cancer remains one of the leading causes of death in the world. For a number of neoplasms, the efficiency of conventional chemo- and radiation therapies is insufficient because of drug resistance and marked toxicity. Plasmonic photothermal therapy (PPT) using local hyperthermia induced by [...] Read more.

Cancer remains one of the leading causes of death in the world. For a number of neoplasms, the efficiency of conventional chemo- and radiation therapies is insufficient because of drug resistance and marked toxicity. Plasmonic photothermal therapy (PPT) using local hyperthermia induced by gold nanoparticles (AuNPs) has recently been extensively explored in tumor treatment. However, despite attractive promises, the current PPT status is limited by laboratory experiments, academic papers, and only a few preclinical studies. Unfortunately, most nanoformulations still share a similar fate: great laboratory promises and fair preclinical trials. This review discusses the current challenges and prospects of plasmonic nanomedicine based on PPT and photodynamic therapy (PDT). We start with consideration of the fundamental principles underlying plasmonic properties of AuNPs to tune their plasmon resonance for the desired NIR-I, NIR-2, and SWIR optical windows. The basic principles for simulation of optical cross-sections and plasmonic heating under CW and pulsed irradiation are discussed. Then, we consider the state-of-the-art methods for wet chemical synthesis of the most popular PPPT AuNPs such as silica/gold nanoshells, Au nanostars, nanorods, and nanocages. The photothermal efficiencies of these nanoparticles are compared, and their applications to current nanomedicine are shortly discussed. In a separate section, we discuss the fabrication of gold and other nanoparticles by the pulsed laser ablation in liquid method. The second part of the review is devoted to our recent experimental results on laser-activated interaction of AuNPs with tumor and healthy tissues and current achievements of other research groups in this application area. The unresolved issues of PPT are the significant accumulation of AuNPs in the organs of the mononuclear phagocyte system, causing potential toxic effects of nanoparticles, and the possibility of tumor recurrence due to the presence of survived tumor cells. The prospective ways of solving these problems are discussed, including developing combined antitumor therapy based on combined PPT and PDT. In the conclusion section, we summarize the most urgent needs of current PPT-based nanomedicine. Full article

(This article belongs to the Special Issue Feature Paper in Optical and Photonic Materials)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Feature Paper in Optical and Photonic Materials

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (12 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI