Смирнов Александр Михайлович
Базовая кафедра «Наноэлектроника и фотоника» при Институте радиотехники и электроники им. В.А. Котельникова РАН
Должности
- Профессор — Базовая кафедра «Наноэлектроника и фотоника» при Институте радиотехники и электроники им. В.А. Котельникова РАН
Био
- · Начал работать в НИУ ВШЭ в 2021 году.
Образование
- 2022 · Доктор физико-математических наук: тема диссертации: Резонансные нелинейно-оптические явления в коллоидных растворах нанокристаллов
- 2015 · Кандидат физико-математических наук: тема диссертации: Самодифракция и нелинейно-оптические свойства экситонов в коллоидных квантовых точках CdSe/ZnS
- 2011 · Специалитет: Московский государственный университет им. М.В. Ломоносова, специальность «Физика конденсированного состояния вещества», квалификация «Физик»
Награды и поощрения
- · Благодарность факультета физики НИУ ВШЭ (март 2025)
- · Надбавка за публикацию в журнале из Списка А (и приравненном к нему научном издании) (2025–2026)
Идентификаторы исследователя
- ORCID:
0000-0003-1724-3925 - ResearcherID:
L-8635-2015 - Scopus AuthorID:
55725392400
Публикации (10)
Temperature-driven charge transport in annealed CdSe/CdS nanoplatelets film
2026 · ARTICLE · en
This work presents a comprehensive investigation into the temperature-dependent thermally stimulated conductivity and photoconductivity of vacuum-annealed thin films based on core–shell CdSe/CdS nanoplatelets passivated with oleic acid ligands. Controlled thermal annealing under vacuum conditions leads to a substantial increase in both dark and photoinduced conductivity, which is primarily attributed to partial desorption of the ligands. This process enhances interparticle electronic coupling while preserving the key optical properties of the nanostructures. Consequently, the fabricated single-layer photodetector demonstrates high responsivity, highlighting the potential of ligand-engineered nanoplatelet films for optoelectronic applications. Detailed analysis of the temperature-dependent conductivity enabled the characterization of hole trapping states within the bandgap of the metamaterial. The extracted effective attempt-to-escape frequency is remarkably low, νeff ≈ 1.5 × 10⁴ s⁻¹, indicating strong carrier localization and large capturing cross section. The density of states can be characterized by Gaussian function with a pronounced maximum at an energy of approximately 0.345 eV above the transport level and a dispersion below 34 meV. These parameters were consistently derived from both thermally stimulated conductivity and photoconductivity measurements through rigorous statistical modeling of thermally released charge carriers. The excellent agreement between the two independent experimental techniques further validates the reliability of the obtained trap-state characteristics.
Optical features of nanoplatelets modified with chiral ligands
2026 · ARTICLE · en
Chiral semiconductor nanostructures and nanoparticles are promising materials for applications in biological sensing, enantioselective separation, photonics, and spin-polarized devices. Here we performed a detailed analysis of optical properties of chiral CdSe nanoplatelets with thickness of 2 and 3 monolayers (ML) with Nacetyl-L-cysteine ligands. We studied the absorption spectra peculiarities, analyzed time-resolved photoluminescence and investigated circular and linear polarization of light passed the samples with different chirality. It was found that non-chiral nanoplatelets reveal the transformation of linear polarization into circular one due to the precence of birefringence. It was demonstrated that only one of the exciton resonances dominates in the polarization properties of chiral nanoplatelets. For chiral 2-ML-thick CdSe nanoplatelets the most pronounced chiral optical response corresponds to the heavy hole excitons and for 3-ML-thick CdSe nanoplatelets light hole excitons play the most important role. We performed complex analysis of the optical features of nanoplatelets modified by chiral ligands and combined for the first time to the best of our knowledge the polarization analysis with time resolved measurements. Moreover, we demonstrated an important role of birefringence in the semiconductor in addition to the presence of chiral ligands, which was not carefully separated before.
Critical behavior of erbium fiber lasers in pulsed and relaxation oscillations regimes
2025 · ARTICLE · en
Miniaturization of erbium fiber lasers is a crucial task, which implies a use of heavily doped fibers. In dense ensemble, interaction of erbium ions changes a configuration of quantum levels of gain medium and leads to pulsed generation. As a result, heavily doped erbium lasers demonstrate two thresholds, the first one associated with an onset of lasing in the pulsed regime, and the second with a transition to CW. Operation features near these two thresholds have been established experimentally. For the first time, a power-law behavior of the system parameters – pulses frequency, duration and peak intensity – was revealed in a wide range of pump rates around both thresholds. The power exponents were associated with critical indices of phase transition. Their values were convincingly determined different from integers and half-integers. Critical indexes were shown weakly dependent on the Fabry-Perot and distributed feedback (DFB) laser cavity parameters, which made it possible to experimentally establish the universal dependence of the pulse frequency and duration on the lasing power. The results of the work are extremely useful for determining and predicting the parameters of the designed erbium lasers, due to universality of the critical indices.
Control under optical, nonlinear optical and kinetic properties of two-dimensional gradient CdSe1-xSx nanocrystals
2024 · ARTICLE · en
Peculiarities of photoluminescence (PL) and absorption spectra of gradient nanocrystals CdSe1-xSx colloidal solution were studied by pump and probe technique under stationary excitation of excitons by nanosecond laser pulses. The PL peaks and differential transmission peaks positions changing were revealed with the CdSe1-xSx nanocrystals composition variation. Bleaching of excitons transitions was observed for high pump intensities and explained by excitons space filling effect. The changing of the differential transmission peaks positions was explained by the nanocrystal band gap dependence on the chemical composition. Time-resolved PL measurements from the sub-picoseconds to tens of nanoseconds range demonstrated a strongly different behavior for gradient nanocrystals and pure CdSe nanocrystals. For pure nanocrystals two typical time-scales were resolved contrary to the gradient nanocrystals where (with the growth of sulfur concentration) only a single time scale was revealed. The observed modification of time-resolved PL for gradient nanocrystals is caused by the presence of traps in the gradient samples due to the chemical composition modification.
Spectral (in)dependence of nonequilibrium charge carriers lifetime and density of states distribution in the vicinity of the band gap edge in F8BT polymer
2023 · ARTICLE · en
Photoelectric properties of the F8BT polymer are investigated by the constant photocurrent (CPM) technique based on the photocurrent spectra Δjph(hν) and absorption spectra αCPM(hν). The lifetime of charge carriers, in the range hν = 2.2–2.7 eV, is found to depend on the photon energy negligibly weakly. The peculiarities of the absorption spectra and the photoconductivity spectra are revealed to determine mainly by the Gaussian distribution of the density of states (DOS). The density of trap states in the F8BT polymer thin films in the exponential DOS is estimated to be 103 times than in the Gaussian DOS.
High Efficient Random Laser with Cavity Based on the Erbium-Doped Germanophosphosilicate Artificial Rayleigh Fiber
2023 · ARTICLE · en
The Erbium “random” laser, based on the artificial Rayleigh fiber, has been comparatively studied in detail under two different pump conditions: 974.5 and 1485 nm pumping wavelengths. The artificial Rayleigh 7-m-long fiber was used as a laser cavity, it was formed by the ultraviolet (UV) inscription of the uniform array of the weakly reflective fiber Bragg grating (FBG) during the fiber drawing process. The UV photosensitivity of the Erbium-doped fiber originated from the specially developed (germanophosphosilicate) core glass composition. The emission spectrum of the fabricated “random” fiber laser had a single narrow peak at the 1548 nm wavelength. It was clearly revealed that the extension of the laser cavity by the separate wavelength-matched 90%-reflective FBG resulted in a significant laser efficiency growth. The highest laser slope efficiency of 33% and the laser output power of 80 mW were reached in the FBG-modified cavity at the 974.5-nm-wavelength pumping. The continuous-wave operation mode of this laser has been confirmed. The laser linewidth value measured by the delayed self-heterodyne technique was about 550 Hz.
Nonlinear Absorption and Photoluminescence of CdTe Nanotetrapods with CdSe Tips under Nonresonance Excitation of Excitons
2023 · ARTICLE · en
The nonlinear absorption and photoluminescence of CdTe/CdSe nanotetrapod colloids have been studied by the pump–probe method for the case of single-photon nonresonance excitation of excitons. A competition between the short-wave and long-wave shifts of the peak of photoluminescence associated with an indirect electron–hole transition, which is observed with increasing excitation radiation intensity, has been found and explained. The former shift is associated with an increase in the one-dimensional exciton radius after the exciton state occupation, and the latter shift may be attributed to the charge-induced Stark effect and local heating of nanotetrapods as a result of electron–phonon interaction at nonresonance excitation of the system.
Photoconductivity and electronic processes in PCDTBT polymer composite with embedded CdSe nanoplatelets
2023 · ARTICLE · en
The photoconductivity in thin films of a new composite based on CdSe nanoplatelets (NPLs) and PCDTBT polymer has been studied using photoconductivity temperature dependences, current-voltage and lux-ampere measurements at various temperatures and applied bias. The incorporation of 7 vol% of NPLs into the polymer blend led to an increase in photoconductivity by an order of magnitude compared to the pristine PCDTBT film in the temperature range of 310–360 K and the electric field strength above 200 V cm−1. An analysis of current-voltage characteristics measured at various temperatures demonstrated that the observed increase in the photoconductivity of the composite is due to a change in the transport mechanism of nonequilibrium charge carriers with an increase in their concentration. The observed saturation of photoconductivity with increasing temperature is supposed to occur due to the increase in exciton diffusion length with temperature increasing and limited effective exciton generation area.
Two-photon excited biexciton photoluminescence in colloidal nanoplatelets CdSe/CdS
2022 · ARTICLE · en
The photoluminescence features under resonant two-photon excitation of a light-hole – electron exciton transition in CdSe/CdS nanoplatelets colloidal solution (536 nm, 1lh-1e) were investigated. The discovered power-law dependence of their photoluminescence intensity on the excitation laser femtosecond pulses intensity was revealed to be relating to biexciton radiation. In addition, the conditions for the photoluminescence growth and quenching were determined depending on the concentration and pump intensity. We believe the results presented in our study will provide a clearer comprehension of the electro-optical processes physics in CdSe/CdS nanoplatelets, which will expand the scope of their application, including frequency up-conversion amplification and lasing, also be beneficial for biosensor design.
Optical gain appearance in the CdSe/CdS nanoplatelets colloidal solution
2022 · ARTICLE · en
The experimental investigations of the colloidal heterostructured CdSe/CdS nanoplatelets transient absorption in the regime of one-photon stationary excitation of excitons by high-intensity nanosecond laser pulses are presented. A strong dependence of exciton’s transitions behavior on nanoplatelets concentration in colloidal solution and pump intensities was studied for the first time. The revealed nonlinear transmission changes of the nanoplatelets solutions with different optical density were explained by the presence of phase space filling effect, energy exchange between exciton states, reabsorption processes and exciton–exciton interaction. The most vital result of the paper is the identification of conditions for the existence of the optical gain in colloidal solutions of nanoplatelets.
Курсы (1)
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Лазерная физика и нелинейная оптика · 3 раза
2025/2026, 2024/2025, 2021/2022 · Магистратура / Магистратура направление: 03.04.02 Физика / Маго-лего · рус