Zakharov, Viktor Valerievich

Burnusuz A., Moshchenskaia M., Prizova V., Shalepo M., Rider M., Zakharov V., Markelov I., Petrov M., Kadyrov D.

AbstractHumans constantly interact with their environment, with other humans, as well as natural and artificial non-human agents. Nevertheless, our somatosensory system limits the diversity of our ways of communicating. Such organisms as plants thus escape our notice, blending into the landscape. This phenomenon is called Plant blindness. This leads not only to indifference and lack of empathy towards plants among ordinary people but also to a deficit in funding plant conservation. We believe that it is important to develop connections and also rethink the relationship between humans and flora. This paper examines the Plant turn in the context of an art-science project titled Plantoverse. The scientific part of the project is based on a study of plant epidermis cells, which possess optical properties and function as a “lens”. The data acquired via confocal microscopy was used to construct a mathematical model of these lenses which in turn formed the basis of the artistic work. It is a representation of the plant epidermis in a digital environment. The work allows us to look at ourselves through “plant optics'' and find new tools for interacting with the vegetal world. This interdisciplinary approach can help transfer knowledge about flora from the professional environment to lay society and form a new, more empathetic view toward plants.

Zakharov V.V., Rider M.A., Kovova M.S., Kuznetsov A., Anikina M.A., Efimova A.A., Kondratev V.M., Shmakov S.V., Kirilenko D.A., Parfenov P.S., Fedorov V.V., Orlova A.O., Bolshakov A.D.

AbstractCarbon dots (CDs) are promising nanostructures in the field of photonics owing to the ease of fabrication, tunable and efficient emission. Gallium phosphide (GaP) nanowires are known for high surface area, optical density, waveguiding, resonant optical properties but lacking the luminescence due to the indirect bandgap. Here, hybrid photonic structures – GaP nanowires decorated with the CDs are fabricated and studied. Feasible drop‐casting deposition technique allows fabrication of dense vertical structures exhibiting efficient photoluminescence. Deposition of the CDs over the nanowires does not affect their luminescent properties demonstrating tolerance of the approach toward the surface aggregation. Tuning of the emission spectrum is obtained via variation of the excitation wavelength and CDs’ synthesis protocol. The structures emitting throughout the visible range are obtained. Analysis of the photoluminescence of an individual structure demonstrates the most intense and fast recombination processes at the ends of a nanowire. It is shown that the luminescence of the CDs’ covering a nanowire acting as a Fabry–Perot cavity is enhanced up to a factor of 3 governed by the Purcell effect. The obtained results unveil a path for fabrication of novel photonic devices via decoration of optically dense nanowires with CDs for enhanced and directed broadband emission.

Tatarinov D., Skurlov I.D., Sokolova A.V., Shimko A.A., Danilov D.V., Timkina Y.A., Rider M.A., Zakharov V.V., Cherevkov S., Kuzmenko N.K., Koroleva A.V., Zhizhin E.V., Maslova Н.A., Stovpiaga E.Y., Kurdyukov D.A., et. al.

Yb3+-CsPbClxBr3−x perovskite nanocrystals with a high two-photon absorption cross-section of 2.3 × 105 GM embedded into amphiphilic silica microspheres emit visible and near-infrared light under two-photon infrared excitation in toluene and water.

Rybin V., Shcherbinin D., Semynin M., Gavenchuk A., Zakharov V., Ivanov A., Rozhdestvensky Y., Rudyi S.

In this paper, we present the nonlinear damping identification method for the fast and comprehensive study of individual microparticles localized in a quadrupole electrodynamic Paul trap. The measurement procedure is discussed in detail. The size, mass and charge of individual silica microspheres from the studied sample are determined simultaneously and non- destructively. Experimental results agree well with the results of independent microscopic examination and density reference values. The further development of the method are outlined.

Stepanova M., Gromova Y., Dubavik A., Maslov V., Orlova A., Zakharov V.

The influence of ultraviolet (UV) laser irradiation on the optical properties of carbon dots (CDs) prepared by the hydrothermal synthesis from citric acid and ethylenediamine has been investigated. Investigation was performed in close-packed carbon films obtained by drop-casting. Observed photoluminescence redshift in films was ascribed to Förster Resonance Energy Transfer (FRET). UV laser irradiation increased carbon dot film light transmission and photoluminescence intensity and leads to a blueshift of photoluminescence. We attribute these changes to CD surface distraction via oxidation that leads to changing of FRET conditions. Controllable changing of carbon dot transmission and photoluminescence parameters by confocal laser irradiation might be used for optical microcoding and the creation of fluorescent labels.

Stepanova M., Kondratev V., Zakharov V., Orlova A.

Composites based on nanomaterials are becoming more popular, especially for the creation of Förster Resonant Energy Transfer systems. Here, well-established zinc oxide tetrapods and a new carbon dot material were used to create a hybrid composite. The influence of the alkalinity of the medium on the formation of the composite was studied. The morphology and optical properties were studied in detail to confirm the formation of the composite. The measurement of photoluminescence lifetimes of carbon dots/zinc oxide tetrapods composites demonstrated nonradiative energy transfer. The efficiency of Förster Resonant Energy Transfer was theoretically calculated and the rate constants of this process, as well as reabsorption, were found. Consequently, the new composite based on carbon dots and zinc oxide tetrapods can find many applications, for example, in optical sensors.

Stepanova M., Dubavik A., Efimova A., Konovalova M., Svirshchevskaya E., Zakharov V., Orlova A.

Multifunctional nanocomposites that combine both magnetic and photoluminescent (PL) properties provide significant advantages for nanomedical applications. In this work, a one-stage synthesis of magneto-luminescent nanocomposites (MLNC) with subsequent stabilization is proposed. Microwave synthesis of magnetic carbon dots (M-CDs) was carried out using precursors of carbon dots and magnetic nanoparticles. The effect of stabilization on the morphological and optical properties of nanocomposites has been evaluated. Both types of nanocomposites demonstrate magnetic and PL properties simultaneously. The resulting MLNCs demonstrated excellent solubility in water, tunable PL with a quantum yield of up to 28%, high photostability, and good cytocompatibility. Meanwhile, confocal fluorescence imaging showed that M-CDs were localized in the cell nuclei. Consequently, the multifunctional nanocomposites M-CDs are promising candidates for bioimaging and therapy.

Brasse G., Loiko P., Grygiel C., Benayad A., Lemarie F., Zakharov V., Veniaminov A., Doualan J., Braud A., Camy P.

Highly doped (20 at.%) Yb 3+ :LiYF 4 single-crystalline thin films are grown on (001)-oriented bulk undoped LiYF 4 substrates by Liquid Phase Epitaxy using lithium fluoride (LiF) as a solvent. The growth temperature lies around 741 °C (0.5–1 °C supercooling) and the growth rate is 1.8–2.6 μm/min. The single-crystalline nature of the films is confirmed by X-ray diffraction and polarized Raman spectroscopy. The film morphology is studied and discussed. The polarized spectroscopic properties of Yb 3+ ions are reported, indicating a stimulated-emission cross-section of 0.88 × 10 −20 cm 2 at 993.9 nm in π-polarization and a radiation trapping free lifetime of the 2 F 5/2 state of 2.00 ms indicating weak concentration-quenching. The crystal-field splitting of Yb 3+ multiplets is resolved at 12 K. Highly-doped Yb 3+ :LiYF 4 /LiYF 4 homoepitaxies are promising for waveguide and thin-disk lasers at ~1 μm. • Liquid Phase Epitaxy growth of 20 at.% Yb:LiYF 4 films on oriented LiYF 4 substrates. • The films crystallize in tetragonal system with a = 5.157 Å and c = 10.714 Å. • Polarized Raman spectra are measured: the maximum phonon energy is 444 cm −1 . • The stimulated-emission cross-section is 0.88 × 10 −20 cm 2 at 993.9 nm in π-polarization. • The crystal-field splitting of Yb 3+ multiplets is resolved at 12 K.

Stepanova M., Dubavik A., Skurlov I., Zakharov V., Rogach A.

Abstract Carbon dots have been modified using UV irradiation (405 nm laser light). UV irradiation of carbon dots has led to various changes in optical properties, which in turn means photomodification of the carbon dots surface. With an increase in light transmission, we have obtained the increasing intensity of photoluminescence and a blue shift by the laser irradiation of the carbon dots. The proposed method can help to adapt and improve the optical properties of carbon dots and can be used in applications, for example, in the optical encryption field.

Kuznetsova V., Osipova V., Tkach A., Miropoltsev M., Kurshanov D., Sokolova A., Cherevkov S., Zakharov V., Fedorov A., Baranov A., Gun’ko Y.

Here we report on the development and investigation of a novel multiplex assay model based on polymer microspheres (PMS) encoded with ternary AIS/ZnS quantum dots (QDs). The system was prepared via layer-by-layer deposition technique. Our studies of Förster resonance energy transfer (FRET) between the QD-encoded microspheres and two different cyanine dyes have demonstrated that the QD photoluminescence (PL) quenching steadily increases with a decrease in the QD-dye distance. We have found that the sensitized dye PL intensity demonstrates a clear maximum at two double layers of polyelectrolytes between QDs and Dye molecules on the polymer microspheres. Time resolved PL measurements have shown that the PL lifetime decreases for the QDs and increases for the dyes due to FRET. The designed system makes it possible to record spectrally different bands of FRET-induced dye luminescence with different decay times and thereby allows for the multiplexing by wavelength and photoluminescence lifetimes of the dyes. We believe that PMS encoded with AIS/ZnS QDs have great potential for the development of new highly selective and sensitive sensor systems for multiplex analysis to detect cell lysates and body fluids’ representative biomarkers.

Kifle E., Loiko P., Romero C., de Aldana J.R., Zakharov V., Gurova Y., Veniaminov A., Petrov V., Griebner U., Thouroude R., Laroche M., Camy P., Aguiló M., Díaz F., Mateos X.

We report on the first, to the best of our knowledge, in-band pumped Tm3+,Ho3+ codoped waveguide (WG) laser. A depressed-index surface channel WG (type III) with a 50 µm half-ring cladding is fabricated in a 5 at. % Tm3+, 0.5 at. % Ho3+:KLu(WO4)2 crystal by femtosecond pulse direct laser writing. Under in-band pumping by a 1679 nm Er Raman fiber laser, Tm3+ and Ho3+ colasing is observed in the WG and explained by bidirectional energy transfer. The maximum total output power at ∼1942nm(Tm3+) and 2059 nm (Ho3+) is 448 mW with a slope efficiencyM of 40.6%, which is a record high for this type of WG lasers. The maximum output power of the Ho laser reaches 144 mW.

Llamas V., Loiko P., Kifle E., Romero C., Vázquez de Aldana J.R., Serres J.M., MauroTonelli, Damiano E., Zakharov V., Veniaminov A., Aguiló M., Díaz F., Chen W., Griebner U., Petrov V., et. al.

Depressed-index low-loss (0.38 dB/cm) buried channel waveguides with a circular cladding are fabricated in bulk Tm3+:SrF2 by ultrafast laser inscription. The waveguide laser generated 148 mW at 1.87 pm with a slope efficiency of 63.9%.

Kifle E., Loiko P., Romero C., de Aldana J.R., Zakharov V., Veniaminov A., Griebner U., Petrov V., Camy P., Braud A., Aguilo M., Diaz F., Mateos X.

We report on the first active surface Y-branch waveguide in the ~2 μm spectral range. Depressed-cladding rectangular-cross-section surface waveguides with a splitting ratio of 1 × 2 are fabricated by femtosecond direct laser writing in a thulium (Tm 3+ ) doped monoclinic double tungstate crystal. Confocal laser microscopy and μ-Raman spectroscopy reveal well preserved crystallinity of the waveguide core. Under high-brightness laser pumping at 0.8 μm, a simultaneous continuous-wave laser operation in both arms is achieved resulting in a total output power of 0.46 W at ~1.84 μm with a slope efficiency of 40.6% and a laser threshold of 0.28 W. The laser output is linearly polarized and spatially multimode (TE12/TE22) with a power splitting ratio between arms of 52.1/47.9%). The waveguide propagation losses at 1.84 μm are ~1.6 dB/cm and the loss from the Y-junction is 0.1 dB. The fabricated waveguides represent a route towards advanced photonic micro-structures such as a Mach-Zehnder interferometer for bio-sensing at ~2 μm.

Kifle E., Loiko P., Vázquez de Aldana J.R., Romero C., Llamas V., Serres J.M., Aguiló M., Díaz F., Zhang L., Lin Z., Lin H., Zhang G., Zakharov V., Veniaminov A., Petrov V., et. al.

Surface channel waveguides (WGs) based on a half-ring (40–60-µm-diameter) depressed-index cladding (type III) geometry are fabricated in monoclinic Tm3+:MgWO4 by femtosecond (fs) laser writing at a repetition rate of 1 kHz. The WGs are characterized by confocal laser microscopy and μ-Raman spectroscopy. A Tm3+:MgWO4 WG laser generates 320 mW at ∼2.02µm with a slope efficiency of 64.4%. The WG emits a transverse single-mode and linear polarization (E||Nm). A remarkable low loss of <0.1dB/cm is measured for the WG. Vibronic laser emission at ∼2.08µm is also achieved.

Llamas V., Loiko P., Kifle E., Romero C., Vázquez de Aldana J.R., Pan Z., Serres J.M., Yuan H., Dai X., Cai H., Wang Y., Zhao Y., Zakharov V., Veniaminov A., Thouroude R., et. al.

Depressed-index buried and surface channel waveguides (type III) are produced in a bulk 3.5 at.% Tm3+:CALGO crystal by femtosecond direct-laser-writing at kHz repetition rate. The waveguides are characterized by confocal microscopy and µ-Raman spectroscopy. Under in-band-pumping at 1679 nm (3H6 → 3F4 transition) by a Raman fiber laser, the buried channel waveguide laser with a circular cladding (diameter: 60 µm) generated a continuous-wave output power of 0.81 W at 1866-1947 nm with a slope efficiency of 71.2% (versus the absorbed pump power) and showed a laser threshold of 200 mW. The waveguide propagation losses were as low as 0.3 ± 0.2 dB/cm. The laser performance under in-band pumping was superior compared pumping at ∼800 nm (3H6 → 3H4 transition), i.e., the convetional pump wavelength. Vibronic laser emission from the WG laser above 2 µm is also achieved. The low-loss behavior, the broadband emission properties and good power scaling capabilities indicate the suitability of Tm3+:CALGO waveguides for mode-locked laser operation at ∼2 µm.

Maestre H., Cuenca M., Ortega A.E.

Abstract This work investigates tunable emission in a continuous-wave Yb:KGW microchip-type solid-state laser utilizing an external cavity. While microchip lasers offer advantages like compactness and simplicity, achieving broad tunability within the compact laser structure presents challenges. The influence of crystal position relative to the pump on the emission polarization was explored. To achieve pump-independent tuning, two external cavity configurations were implemented, including a Littrow configuration with a diffraction grating and a configuration employing a bandpass filter. The filter-based configuration demonstrated superior performance, enabling a tuning range exceeding 35 nm. The obtained results demonstrate the potential of external cavity techniques to enhance the tunability and performance of microchip lasers for applications requiring wavelength-agile sources.

Nikitin I.Y., Borodina L.N., Boltenko A.V., Baranov M.A., Gladskikh I.A., Vartanyan T.A.

Ortiz-Vergara V.A., Garza-Navarro M.A., González-González V.A., López-Cuellar E., Estrada-de la Vega A.

Sumiya T., Tani S., Tsunoda A., Nakazaki M., Kobayashi Y.

We demonstrated a monolithic waveguide laser in Er:YAG ceramics fabricated using femtosecond direct laser writing. High-quality Er:YAG ceramics with precisely controlled Er-ion doping were synthesized, providing an optimal medium for laser and amplifier applications. Waveguide structures were inscribed within the ceramics to support low-loss propagation with a large mode area. A monolithic laser cavity was formed by applying dielectric multilayer coatings to the waveguide facets. The waveguide laser, pumped at a wavelength of 1532 nm, achieved 82 mW output and 27% slope efficiency at a wavelength of 1645 nm. Single-longitudinal-mode operation was achieved at 11 mW.

Fernandes T.V., Bordon C.D., Wetter N.U., de Rossi W., Kassab L.R.

This study is focused on the fabrication and characterization of various dual waveguides through femtosecond (fs) laser irradiation of GeO2-based glass samples. The objective of the present work is to develop diverse waveguide configurations, namely straight, S-bend and Y-shaped waveguides within GeO2–PbO glasses embedded with silver nanoparticles, utilizing a double-guide platform, for photonic applications such as resonant rings and beam splitters. Enhanced guidance was observed with a larger radius of curvature (80 mm) among the two distinct S-bend waveguides produced. The maximum relative propagation loss was recorded for the S-bend waveguide with a 40 mm radius, while the minimum loss was noted for the Y-shaped waveguide. In the latter configuration, with an opening angle of 5° and a separation of 300 µm between the two arms, an output power ratio of 50.5/49.5 between the left and right arms indicated promising potential for beam splitter applications. During the study, the quality factor (M2) of the proposed architectures was measured and the 80 mm S-bend configuration presented the best symmetry between the x and y axes; in the case of the Y configuration the similarity between the M2 values in both axes, for the first and second arms, indicates comparable light guidance.

Litvin A.P., Guo J., Wang J., Zhang X., Zheng W., Rogach A.L.

AbstractMetal halide perovskite nanoplatelets (NPls) possess ultra‐narrow photoluminescence (PL) bands tunable over the entire visible spectral range, which makes them promising for utilization in light‐emitting diodes (LEDs) with spectrally pure emission colors. This calls for development of synthetic methods toward perovskite NPls with a high degree of control over both their thickness and lateral dimensions. A general strategy is developed to obtain such monodisperse CsPbI3 NPls through the control over the halide‐to‐lead ratio during heating‐up reaction. The excess of iodine precursor changes the chemical equilibrium, thus yielding monodisperse (3 monolayers in thickness) CsPbI3 NPls whose PL width constitutes ≈22 nm, while the lateral dimensions of NPls are determined by choice of precursor and by the reaction temperature. Postsynthetic cation exchange on the A‐site of the perovskite lattice allows for the tuning of the PL peak position, while simultaneous removal of the excess ligands and the surface passivation allows for improvement of the PL quantum yield to 96% and ensures superior stability of optical properties upon storage. Electroluminescent LEDs with the peak values are fabricated for the external quantum efficiency and luminance being 9.45% and 29800 cd m−2, respectively, and a narrow (≈26 nm) electroluminescence peak at 601 nm.

Li M., Yin Q., Xu R., Wang X., Huang X., Chen Z., Ma T., Chen J., Zeng H.

Lead‐halide perovskites are a new class of semiconductor materials that have excellent optoelectronic properties and can be easily transformed into bright luminescent colloidal nanocrystals. These characteristics bring great prospects for the development of high‐efficiency optical devices. These materials possess unique anion‐exchange properties that allow for post‐synthesis adjustment of the bandgap. Anion exchange typically initiates at the surface: Perovskite nanocrystals have flexible lattice properties, which allow ions to gradually diffuse into the interior of the crystal with the help of vacancies, resulting in the formation of complete or mixed‐phase perovskites. Various methods, such as liquid phase, gas phase, and solid phase anion exchange, enable precise control over the composition and bandgap modulation, thereby tuning the emission wavelengths of nanocrystals across the visible spectrum. The flexibility and precision offered by anion exchange facilitate effective phase control and engineering of the optoelectronic properties of lead‐halide perovskites. This, in turn, opens up opportunities for their application in light‐emitting diodes, solar cells, and detectors, thus driving further advancements in anion‐exchange technology.

Yang T., Wang Y., Liao L.

AbstractGiven the extensive application of near‐infrared (NIR) emission, the quest for efficient and versatile NIR semiconductors have attracted tremendous attention. Leveraging trivalent rare earth (RE3+) ions doping, the integration of metal halide perovskites with RE3+ ions makes it easy to achieve NIR‐II emission (1000–1700 nm). However, although showing promise in bioimaging, optical communication, and night vision, enhancing NIR‐II emission intensity to promote further progress in real‐world applications remains a challenge. This review summarizes the recent advancements in RE3+ ion‐doped perovskite NIR semiconductors, and discusses what kind of properties are needed and how to achieve desired optical properties in various applications. The review starts with the synthesis methods for various material types with rich examples. Following this, the mechanisms of strategies for optimizing NIR luminescence performance are discussed in detail. Furthermore, the review highlights their multifunctional applications both as an electrically driven emitter in NIR light‐emitting diodes (LEDs) and as a down‐conversion emitter in photovoltaic devices (PVs) or phosphor‐converted LEDs (pc‐LEDs). Finally, insights on how to fill the gap between current research and future goals are provided. This review aims to provide a deeper understanding of RE3+ ion‐doped NIR light‐emitting perovskite materials, and to promote the exploration of efficient NIR emitters.

Ayevi B., Morova Y., Morova B., Damiano E., Tonelli M., Sennaroglu A.

We report on the operation of an efficient Tm,Ho:YLF depressed cladding, channeled waveguide laser in both continuous-wave (CW) and passively Q-switched (PQS) regimes, producing laser emission at the wavelength of 2.05 µm. The 70-µm diameter depressed cladding waveguide, fabricated using femtosecond laser inscription, had a low propagation loss value of 0.14 dB/cm and a refractive index contrast of 8.3 × 10−4. In the CW regime, the waveguide laser was excited at 780 nm, and an output power of up to 2 W was generated at the incident pump power of 4.14 W with a power slope efficiency of 50.0%. PQS operation was further realized by utilizing a Cr:ZnSe saturable absorber (SA), whereby the waveguide laser generated as short as 19.6-ns pulses with a power slope efficiency of 18.9%.

Wang M., Salter P., Payne F., Liu T., Booth M., Fells J.

In this paper, we demonstrate the integration of photonic devices on sapphire substrates using multi-layer depressed cladding waveguides at both 780 nm and 1550 nm. The devices are up to 10 cm long and written at depths down to 800 µm. The propagation losses for single-mode guiding are ∼ 0.6 dB/cm at 780 nm and ∼ 0.7 dB/cm at 1550 nm. A number of structures have been fabricated with simultaneous single-mode and polarization independent operation: evanescently coupled waveguide arrays, Y-branch splitters, Mach-Zehnder interferometers, and a 2 × 2 directional-coupler. All the devices were fabricated using adaptive optics-assisted femtosecond laser direct writing with a customized laser writing algorithm. This work enables the integration of single-mode sapphire photonics devices in a scalable manner, enabling many applications in communications, imaging, computing, and sensing.

Gomide G., Fiuza T., Campos A.F., Cannas M., Sciortino A., Messina F., Depeyrot J.

Tkach A.P., Miropoltsev M.A., Kundelev E.V., Sokolova A.V., Khorkina S.A., Rogach A.L., Bogdanov K.V.

Wang Y., Kang C.H., Maity P., Ng T.K., Mohammed O.F., Ooi B.S.

Li S., Song Y., Ma L.

Timkina Y.A., Skurlov I.D., Tatarinov D.A., Batueva E.A., Ismagilov A.O., Kuzmenko N.K., Koroleva A.V., Zhizhin E.V., Xie J., Huang H., Ushakova E.V., Litvin A.P.

Tepliakov N.V., Sokolova A.V., Tatarinov D.A., Zhang X., Zheng W., Litvin A.P., Rogach A.L.

Pan J., Shen W., Li S., Zhang Z., Zhao F., Duan H., Wang Y., Liao L.

Roh J.Y., Milstein T.J., Gamelin D.R.

Kuznetsov A., Roy P., Grudinin D.V., Kondratev V.M., Kadinskaya S.A., Vorobyev A., Kotlyar K.P., Ubyivovk E., Fedorov V.V., Cirlin G.E., Mukhin I., Arsenin A.V., Volkov V., Bolshakov A.D.

Semiconductor nanowires are the perfect platform for nanophotonic applications owing to their resonant, waveguiding optical properties and technological capabilities providing control over their crystalline and chemical composition. Vapor-liquid-solid growth mechanism...

Kuznetsov A., Moiseev E., Abramov A.N., Fominykh N., Sharov V.A., Kondratev V.M., Shishkin I.I., Kotlyar K.P., Kirilenko D.A., Fedorov V.V., Kadinskaya S.A., Vorobyev A.A., Mukhin I.S., Arsenin A.V., Volkov V.S., et. al.

AbstractEmerging technologies for integrated optical circuits demand novel approaches and materials. This includes a search for nanoscale waveguides that should satisfy criteria of high optical density, small cross‐section, technological feasibility and structural perfection. All these criteria are met with self‐assembled gallium phosphide (GaP) epitaxial nanowires. In this work, the effects of the nanowire geometry on their waveguiding properties are studied both experimentally and numerically. Cut‐off wavelength dependence on the nanowire diameter is analyzed to demonstrate the pathways for fabrication of low‐loss and subwavelength cross‐section waveguides for visible and near‐infrared (IR) ranges. Probing the waveguides with a supercontinuum laser unveils the filtering properties of the nanowires due to their resonant action. The nanowires exhibit perfect elasticity allowing fabrication of curved waveguides. It is demonstrated that for the nanowire diameters exceeding the cut‐off value, the bending does not sufficiently reduce the field confinement promoting applicability of the approach for the development of nanoscale waveguides with a preassigned geometry. Optical X‐coupler made of two GaP nanowires allowing for spectral separation of the signal is fabricated. The results of this work open new ways for the utilization of GaP nanowires as elements of advanced photonic logic circuits and nanoscale interferometers.

Mihalcea B.M., Filinov V.S., Syrovatka R.A., Vasilyak L.M.

Charged microparticles confined in electrodynamic traps evolve into strongly coupled Coulomb systems (SCCS) which are the subject of current investigation. Recent results with respect to particle dynamics in linear and nonlinear Paul traps are reviewed, including the case of a confined microparticle in presence of an acoustic wave. An analytical model is used to discuss dynamical stability for a system of two coupled ions confined in a Paul trap. The model is then extended to discuss quantum stability for many-body systems of trapped ions. Dynamical stability for many-body systems of identical ions confined in 3D quadrupole ion traps (QIT) is studied locally, in the neighbourhood of minimum configurations that characterize ordered structures. The analytical model is particularized to the case of a combined trap. It is demonstrated that Paul (ion) traps are versatile instruments to investigate one-component strongly coupled Coulomb systems (microplasmas). Exciting physical phenomena associated to Coulomb systems are reported such as autowave generation, phase transitions, defect formation, system self-locking at the edges of a linear Paul trap, self-organization in layers, or pattern formation and scaling. The dynamics of ordered structures consisting of highly nonideal similarly charged solid particles with coupling parameter of the order Γ=108 is explored. The approach used enables one to explore the interaction of microparticle structures in presence and in absence of the neutralizing plasma background, as well as to investigate various types of phenomena and physical forces experienced by these patterns. Brownian dynamics (BD) is used to characterize charged particle evolution in time and thus identify regions of stable trapping. Analytical models are used to explain the experimental results. Numerical modelling considers stochastic forces of random collisions with neutral particles, viscosity of the gas medium, regular forces produced by the a.c. trapping voltage, and gravitational force. Microparticle dynamics is characterized by a stochastic Langevin differential equation. Laser plasma acceleration of charged particles is also discussed, with an emphasis on Paul traps employed to investigate collective effects in space-charge-dominated (relativistic) beams, and for target micropositioning. This review paper is both an add-on as well as an update on late progress in SCCS confined in electrodynamic traps.

Yu Y., Zou C., Shen W., Zheng X., Tian Q., Yu Y., Chen C., Zhao B., Wang Z., Di D., Bakr O.M., Liao L.

Tatarinov D., Sokolova A.V., Skurlov I.D., Danilov D.V., Koroleva A.V., Kuzmenko N.K., Timkina Y.A., Baranov M., Zhizhin E.V., Tsypkin A., Litvin A.P.

Currently, lead halide perovskite nanostructures are an essential platform for designing new optical materials with required functionalities. Photoluminescence (PL) wavelength tuning is an important tool for targeted applications of optical...

Khait I., Lewin-Epstein O., Sharon R., Saban K., Goldstein R., Anikster Y., Zeron Y., Agassy C., Nizan S., Sharabi G., Perelman R., Boonman A., Sade N., Yovel Y., Hadany L.

Stressed plants show altered phenotypes, including changes in color, smell, and shape. Yet, airborne sounds emitted by stressed plants have not been investigated before. Here we show that stressed plants emit airborne sounds that can be recorded from a distance and classified. We recorded ultrasonic sounds emitted by tomato and tobacco plants inside an acoustic chamber, and in a greenhouse, while monitoring the plant’s physiological parameters. We developed machine learning models that succeeded in identifying the condition of the plants, including dehydration level and injury, based solely on the emitted sounds. These informative sounds may also be detectable by other organisms. This work opens avenues for understanding plants and their interactions with the environment and may have significant impact on agriculture.

Greant C., Van Durme B., Van Hoorick J., Van Vlierberghe S.

Zi L., Song J., Wang N., Wang T., Li W., Zhu H., Xu W., Song H.

Shen X., Wang Z., Tang C., Zhang X., Lee B.R., Li X., Li D., Zhang Y., Hu J., Zhao D., Zhang F., Yu W.W., Dong B., Bai X.

Rybin V., Rudyi S., Rozhdestvensky Y.

We propose a Nonlinear Damping Identification method for charged nano- and microparticles in a linear quadrupole Paul trap under nonlinear damping forces. We analytically and numerically evaluate conditions for the formation of plane limit cycle trajectories, i.e. “extended orbits” in spherical particle approximation. We introduce numerical metrics for such orbits and define a functional relation between the metrics and physical parameters of a trapped particle: size, mass, and charge. The method proposed allows non-destructive, simultaneous and separate determination of the trapped particle parameters in a wide range of sizes. • Extended orbits, the limit cycles of particle motion in a quadrupole Paul trap, are formed under nonlinear drag force. • Spectral composition of the extended orbit is uniquely determined by the size-mass-charge ratios of a trapped mesoscopic particle. • Nonlinear dynamics analysis of a trapped charged nano- and microparticle allows determining its size, mass, and charge non-destructively, simultaneously, and independently.

Sokolova A.V., Tepliakov N.V., Ismagilov A.O., Tatarinov D.A., Kalinichev A.A., Koroleva A.V., Zhizhin E.V., Baranov M.A., Ushakova E.V., Litvin A.P.

Stepanova M., Gromova Y., Dubavik A., Maslov V., Orlova A., Zakharov V.

The influence of ultraviolet (UV) laser irradiation on the optical properties of carbon dots (CDs) prepared by the hydrothermal synthesis from citric acid and ethylenediamine has been investigated. Investigation was performed in close-packed carbon films obtained by drop-casting. Observed photoluminescence redshift in films was ascribed to Förster Resonance Energy Transfer (FRET). UV laser irradiation increased carbon dot film light transmission and photoluminescence intensity and leads to a blueshift of photoluminescence. We attribute these changes to CD surface distraction via oxidation that leads to changing of FRET conditions. Controllable changing of carbon dot transmission and photoluminescence parameters by confocal laser irradiation might be used for optical microcoding and the creation of fluorescent labels.