Photophysics of single LX centers in high pressure

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Photophysics of single LX centers in high pressure–high temperature microdiamonds

Physical Review B: Condensed Matter and Materials Physics. 2025. Vol. 111. No. 15.

Нелюбов А. Ю., Tarasevich A., Павленко М. И., Екимов Е., Наумов А. В., Еремчев И. Ю.

LX centers are a recently discovered class of impurity centers in diamonds, which are characterized by nearly phononfree, spectral narrowband, and intense fluorescence at room temperature. Such a set of properties pave the way for a variety of applications, including sensing and single-photon emission. The latter requires a detailed study of photophysical processes of single emitters, which is the focus of this paper. The study of the luminescence dynamics of single LX centers in microdiamonds, synthesized by the high pressure-high temperature method, is performed by means of second-order cross-correlation function (𝑔(2)) analysis. Even though the blinking is not observed directly in the measurements, the presence of photon bunching indicates that the fluorescence of a single emitter is intermittent at microsecond scale. The three-level system that is commonly used to describe intermittency of dye molecules is not consistent with the observed power dependences. We suggest a four-level energy system model with two metastable states to describe the results and perform numerical simulations to validate the model. Finally, we discuss the four-level model in the form of fluctuations of photophysical parameters.

Research target: Physics

InGaAsN/GaAs quantum-well-based microlasers improved by PECVD SiO2 passivation

Войтович В. И., Makhov I., Мельниченко И. А. et al., Optics Letters 2026 Vol. 51 No. 17 P. 4872–4875

The influence of cavity surface passivation with SiO2 coating deposited by the plasma-enhanced chemical vapor deposition technique is investigated for injection microdisk lasers with an InGaAsN/GaAs quantum well active region. The electroluminescence spectra of the microdisk lasers with cavity diameters ranging from 12 to 32 μm with and without sidewall surface passivation were studied for a ...

Added: September 25, 2026

Микролазеры с распределенными брэгговскими отражателями Al0.2Ga0.8As/Al0.9Ga0.1As

Бабичев А. В., Makhov I., Kryzhanovskaya N. et al., Оптика и спектроскопия 2026 Т. 134 № 3 С. 272–277

Представлены результаты по реализации генерации при повышенных температурах в лазерах с длиной волны генерации 980 nm на основе вертикального микрорезонатора с использованием непоглощающих на длине волны оптической накачки зеркал. Минимальная пороговая мощность накачки составила ~0.8 mW и соответствовала температуре 150 K. Добротность микрорезонатора, определенная на пороге генерации, превысила 13000. Максимальная рабочая температура микролазера составила 195 ...

Added: September 25, 2026

Одночастотная генерация лазеров на основе вертикального микрорезонатора при комнатной температуре

Бабичев А. В., Makhov I., Kryzhanovskaya N. et al., Письма в Журнал технической физики 2026 Т. 52 № 12 С. 40–43

Реализована одночастотная генерация при 300 K в лазерах на основе вертикального микрорезонатора. Для лазеров с полупроводниковым выводным зеркалом пороговая плотность мощности накачки составила 6.5 kW/cm2. Добротность микрорезонатора и длина волны излучения, определенные на пороге генерации, равнялись 8800 и ~ 959.8 nm. Применение конструкции микрорезонатора с гибридным выводным зеркалом позволило повысить добротность микрорезонатора (до 12 360) ...

Added: September 25, 2026

Высокодобротные планарные микрорезонаторы, обеспечивающие генерацию при комнатной температуре

Бабичев А. В., Makhov I., Kryzhanovskaya N. et al., Письма в Журнал технической физики 2026 Т. 52 № 18 С. 30–34

Представлены результаты реализации генерации при комнатной температуре в планарных вертикальных микрорезонаторах на основе зеркал Al0.2Ga0.8As/Al0.9Ga0.1As. При 300 K пороговая плотность мощности и добротность на пороге генерации составили 11.4± 0.7 kW/cm2 и 5070± 160 соответственно. Двукратное превышение порога генерации привело к увеличению добротности микрорезонатора до 19 000. Эффективный латеральный теплоотвод подтвержден малым сдвигом энергии кванта, который составил ...

Added: September 25, 2026

Critical dynamics of conformational exchange in a nearcritical solvent: A statistical-mechanical three-mode theory

Budkov Y., Kiselev M. G., Journal of Chemical Physics 2026 Vol. 165 No. 12 Article 124508

We develop a three-mode statistical-mechanical theory for a two-conformer solute in a near-critical solvent. A compressible lattice model with vacancies yields the Gaussian free-energy functional for a critical conserved density, an orthogonal noncritical conserved mode, and the local conformer fraction. Their couplings follow from packing and cohesive interactions, rather than being introduced phenomenologically. Kawasaki transport of the two conserved fields and ...

Added: September 24, 2026

Room temperature microlasers based on quasi-planar geometry

Kryzhanovskaya N., Makhov I., Dragunova A., St. Petersburg Polytechnical University Journal: Physics and Mathematics 2026 Vol. 19 No. 1.1 P. 98–104

The planar microcavity structure was grown using molecular-beam epitaxy. Single-mode lasing was observed at a wavelength of 960 nm for pillars with a diameter of 15 μm. At 300 K, the lasing threshold was approximately 30 mW. Increasing the pump power to 2.7 times the threshold power resulted in a mode energy shift of approximately 1 meV. This shift ...

Added: September 23, 2026

Plasma excitations in thin-film NbN probed by terahertz spectroscopy

Andreeva S., Gavrilov A. A., Dzhikirba K. R. et al., Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 114 Article 134515

We examine plasma excitations with linear dispersion in a system of superconducting electrons in thin NbN disks. Using frequency-domain terahertz spectroscopy, we study the evolution of plasmons up to critical temperature Tc. The observed excitations tend to shift to the lower frequencies while temperature is increasing and the spectral features vanish at T > Tc. We study the ...

Added: September 23, 2026

Thermo-optically tuned single-mode limaçon microlaser on quantum-dots

Образцова А. А., Ivanov K., Moiseev E. et al., Journal of Physics D: Applied Physics 2026 Vol. 59 No. 30 P. 305103

We demonstrate a thermo-optically tunable microlaser based on an InGaAs/GaAs quantum-dot (QD) active region employing a deformed limaçon-shaped cavity. The asymmetric geometry effectively lifts the degeneracy of high-Q whispering-gallery modes, enabling single-mode lasing. A side-mode suppression ratio exceeds 25 dB over a wide current range. Under continuous-wave electrical pumping, the device achieves a peak output power ...

Added: September 23, 2026

Exact screening constraints for theories of inhomogeneous electrolytes: Generalized Stillinger–Lovett relations and a nonlinear Ward hierarchy

Budkov Y., Journal of Chemical Physics 2026 Vol. 165 No. 12 Article 124105

Exact theories of electrolyte structure must satisfy the nonlocal constraints imposed by electrostatic screening, yet these constraints are most commonly formulated only for homogeneous bulk systems and at the level of two-point correlations. Here, we develop a unified field-theoretic framework that extends them to general inhomogeneous ionic fluids and nonlinear charge correlations. Using a standard ...

Added: September 22, 2026

Особенности взаимодействия мощного импульсного лазерного излучения с материалами вакуумной камеры термоядерного реактора

Боровицкая И. В., Пименов В. Н., Коршунов С. Н. et al., Перспективные материалы 2026 № 10 С. 37–54

Проведено сравнение, обобщение и систематизация механизмов эрозии и разрушения поверхности малоактивируемых материалов, перспективных для использования в качестве материалов вакуумной камеры термоядерных реакторов: ванадия, его сплава V – 10 Ti – 6 Cr – 0,05 Zr – 0,1 Si и вольфрама при последовательном воздействии на них ионных и тепловых потоков. Тепловые потоки имитировали с помощью мощного импульсного лазерного излучения (ЛИ), создаваемого ...

Added: September 22, 2026

DOUBLE-RESONANCE RESPONSE OF A SUPERCONDUCTING QUANTUM METAMATERIAL: MANIFESTATION OF NONCLASSICAL STATES OF PHOTONS

Iontsev M.A., Mukhin S. I., Fistul M. V., Physical Review B: Condensed Matter and Materials Physics 2016 Vol. 94 No. 17 P. 174–510

We report a theoretical study of the ac response of superconducting quantum metamaterials (SQMs), i.e., an array of qubits (two-level systems) embedded in a low-dissipative resonator. By making use of a particular example of a SQM, namely the array of charge qubits capacitively coupled to the resonator, we obtain a second-order phase transition between an ...

Added: September 22, 2026

Interaction-limited conductivity of twisted bilayer graphene revealed by giant terahertz photoresistance

Shilov A. L., Elesin L., Kravtsov M. et al., Nature Communications 2026 Vol. 17 No. 1 Article 9734

Identifying the microscopic processes limiting conductivity is essential for understanding correlated quantum materials. In twisted bilayer graphene, metallic resistivity follows ρ ~ Tα with widely varying α, fueling competing interpretations from phonon-limited transport and umklapp scattering to strange metallicity and heavy-fermion renormalization. Here, we use terahertz excitation to selectively heat electrons while keeping the lattice cold, separating ...

Added: September 20, 2026

RL-ABC: Reinforcement learning for accelerator beamline control

Ibrahim A., Derkach D., Kaledin M. et al., Computer Physics Communications 2026 Vol. 329 Article 110407

We present RLABC (Reinforcement Learning for Accelerator Beamline Control), an open-source Python framework that automatically transforms standard Elegant beamline configurations into reinforcement learning environments. RLABC integrates with the widely-used Elegant beam dynamics simulation code via SDDS-based interfaces, enabling researchers to apply modern RL algorithms to beamline optimization with minimal RL-specific development. Validation on a test ...

Added: September 20, 2026

Drift Towards Isotropization during the 3D Hydrodynamic Turbulence Onset

Копьев А., JETP Letters 2026 Vol. 123 No. 5 P. 310–316

The incompressible three-dimensional Euler equations develop very thin pancake-like regions of exponen tially increasing vorticity. The characteristic thickness of such regions decreases exponentially with time, while the other two dimensions do not change considerably, making the flow near each pancake strongly anisotropic. The pancakes emerge in increasing number with time, which may enhance the anisotropy ...

Added: September 18, 2026

Bis(1,2,4-triphenylcyclopentadienyl) Terbium 4,4,4-trifluoro-1-phenylbutane-1,3-dionate

Daniil A. Bardonov, Minyaev M. E., Puntus L. et al., MolBank 2025 Vol. 2025 No. 4 Article M2102

A new bis(cyclopentadienyl) terbium(III) complex with 1,2,4-triphenylcyclopentadienyl and 4,4,4-trifluoro-1-phenylbutane-1,3-dionate ligands was synthesized. Single-crystal X-ray analysis revealed a mononuclear bis(cyclopentadienyl) complex with a diketonate ligand in the bisector plane. The compound under study exhibits a ligand ligand charge transfer state (LLCT), according to optical spectroscopy and crystallographic data. ...

Added: February 19, 2026

Photoinduced Tautomerisation of ESIPT-Capable Iridium(III) Complexes with Rationally Designed Acyclic Diaminocarbene Ligands

Bezzubov S., Tatarin S., Kinzhalov M. et al., Inorganic Chemistry 2026 Vol. 65 No. 3 P. 1793–1800

A series of ESIPT-capable IrIII-(acyclic diaminocarbene species) (ESIPT = Excited-state intramolecular proton transfer) exhibiting strong photoluminescence properties is described. The emission profile is strongly influenced by the nature of the azaheterocyclic fragment in the diaminocarbene ligand: pyrazine-derived species display phosphorescence bands red-shifted by approximately 100 nm compared to their pyridine analogues. This redshift is attributed ...

Added: February 17, 2026

Cyclometalated iridium(III) complexes with acyl-pyrazolone ligands – towards tunable versatile building blocks and AIE emitters with external chelating fragments

Tatarin S., Meshcheriakova E., Korshunov V. et al., Optical Materials 2026 Vol. 172 Article 117806

Development of stimuli-responsive emissive materials is of great importance, and design of transition metal complexes with varying number of external chelating fragments may contribute to this field. In this work, three bis-cyclometalated iridium complexes with 2-acyl-pyrazolone ligands in both metalated and ancillary modes were synthesized and studied by various spectroscopic techniques, single-crystal X-ray diffraction and ...

Added: February 15, 2026

New Manganese(II) Coordination Compounds with 4-((1H-Pyrrol-2-yl)methylene-amino)-4H-1,2,4-triazole

Bovkunova A., Bazhina E., Shmelev M. et al., Russian Journal of Coordination Chemistry/Koordinatsionnaya Khimiya 2025 Vol. 51 No. 6 P. 472–487

The reaction of manganese(II) chloride with the azomethine ligand 4-((1H-pyrrol-2-yl)methylene-amino)-4H-1,2,4-triazole (HPyrtrz) affords crystals of 1D polymeric compound [MnII(HPyrtrz)(H2 O)Cl2]n (I). The addition of the coligand 1,10-phenanthroline (Phen) to the synthesis of compound I results in the sequential crystallization of two products: 1D polymeric compound [MnII(Phen)Cl2]n (II) and mononuclear complex [MnII(Phen)2Cl2]·HPyrtrz (III). Complex III is isolated ...

Added: February 10, 2026

New Carboxylate Anionic Sm-MOF: Synthesis, Structure and Effect of the Isomorphic Substitution of Sm3+ with Gd3+ and Tb3+ Ions on the Luminescent Properties

Ivanova A., Gontcharenko V., Lunev A. et al., Inorganics 2022 Vol. 10 No. 8 Article 104

Two new compounds, namely {(NMe2H2)}[Ln(TDA)(HCOO)] 0.5H2O, Ln = Sm3+ (Sm-TDA) and Gd3+ (Gd-TDA), where TDA3− is the anion of 1H-1,2,3-triazole-4,5-dicarboxylic acid (H3TDA), were synthesized by the solvothermal method in a DMF:H2O mixture. According to single-crystal X-ray diffraction data, the compounds are 3d-MOFs with an anionic lattice and dimethylammonium cations occupying part of the cavities. Based ...

Added: January 13, 2026

Europium Coordination Compounds for the Design of a Polyethylene-Based Luminescent Composite Material

Roitershtein D., Puntus L., Varaksina E. et al., Russian Journal of Coordination Chemistry/Koordinatsionnaya Khimiya 2025 Vol. 51 No. 3 P. 218–225

The reaction of europium dibenzoylmethanate complex Na+[Eu(Dbm)4]– with 1-alkyl-4-dimethylaminopyridinium salts gives compounds [RNC5H4NMe2]+[Eu(Dbm)4]– (Dbm = [PhC(O)CHC(O)– Ph]), where R = C10H21 (I) or a set of oligomers CnH2n+1, (n is even) ([(R-NC5H4NMe2)]I) with a weightaverage molecular weight Mw = 1520 (II). The molecular structure of complex I was established by X-ray diffraction analysis (CCDC no. 2405293). Compounds I and ...

Added: November 9, 2025

Effect of sodium and cerium co-doping on microstructure and luminescent properties of hydroxyapatite ceramics

Petrakova N., Demina A., Zobkova Y. et al., Journal of Alloys and Compounds 2025 Vol. 1037 Article 181865

The hydroxyapatite powders with co-doping of Ca2+ with Na+ and Ce3+ were obtained by aqueous precipitation. Co-doping was considered as a method of charge compensation in the cationic sublattice of the HA structure by means of the 2Ca2+→Ce3+ + Me+ in order to maintain the stability of phase composition, improve the optical and microstructural properties of the HA ...

Added: November 5, 2025

Hybrid Nature of Metastable Nonradiative Recombination Centers in Perovskites: Merging Shallow and Deep Defect States

Tarasevich A., Li J., Kniazeva M. et al., PRX Energy 2025 Vol. 4 No. 2 Article 023005

Metastable nonradiative centers (supertraps) are significant energy loss channels in perovskite optoelectronic devices. In their active state, supertraps induce substantial energy loss through nonradiative recombination of free charge carriers. Transitions between active (energy loss) and passive (no energy loss) states result in photoluminescence (PL) blinking on timescales from milliseconds to seconds. The presence of blinking allowed us to ...

Added: April 30, 2025

Высокодобротные состояния в спектрах излучения линейных периодических цепочек Si-нанодисков со встроенными GeSi-квантовыми точками

Зиновьев В. А., Смагина Ж. В., Зиновьева А. Ф. et al., Физика и техника полупроводников 2024 Т. 58 № 5 С. 238–241

In this work the luminescent properties of structures with linear periodic chains of Si nanodisks with embedded GeSi quantum dots were studied. It was found that the formation of linear chains of resonators leads to a change in the intensity and directivity of quantum dots emission. Narrow high-Q peaks that are associated with collective modes ...

Added: November 24, 2024

The pathways of electronic excitation back energy transfer processes (BET) in novel Eu3+ heterocyclic 1,3-diketonates bearing a perfluorinated moiety

Korshunov V., Kiskin M., Taydakov I., Journal of Luminescence 2022 Vol. 251 Article 119235

A series of novel brightly emitting Eu3+ coordination compounds with 1,3-diketones bearing a thiophene moiety and a linear CnF2n+1 chain (n = 1–8) were synthesized and fully characterized. The dependence of back energy transfer (BET) processes on the fluorinated chain length of the ligand environment was investigated in detail. The rates of radiative, non-radiative, and ...

Added: November 23, 2024