2018 International Conference Laser Optics (ICLO), 2018
An experimental technique for measuring the statistics of photocounts for pulsed low-photon light... more An experimental technique for measuring the statistics of photocounts for pulsed low-photon light sources using a SiPM detector is proposed
We study multiphoton processes in optical active organic microrods and microspheres made by self-... more We study multiphoton processes in optical active organic microrods and microspheres made by self-assembly technique which are perspective for possible applications as active waveguides and whispering gallery mode microresonators.
Plasmonic structures are extremely attractive for the light flow manipulation. In turn, the spect... more Plasmonic structures are extremely attractive for the light flow manipulation. In turn, the spectrum of the plasmon excitations can be controlled by external magnetic field, thus giving rise to magnetoplasmonics. However, in the case of traditional magnetoplasmonic structures, the enhancement of magneto-optical (MO) effects is often accompanied by the transmission damp, which constricts the area of their applications. This paper examines resonant optical effects in composite structures based on artificial opal films covered by a thin cobalt layer, which forms a 2D hexagonal lattice of nanoholes in the metal film. Such periodic structure exhibits surface plasmon polariton-assisted extraordinary transmission along with the increase of odd in magnetization intensity magnetooptical effect in the Voigt geometry. Local field enhancement accompanying the surface plasmon polaritons excitation in composite Co/opal structure provides a distinct enhancement of the magnetization-induced second ...
Journal of Experimental and Theoretical Physics, 2020
Specific features of optical second harmonic (SH) generation in arrays of chiral helical nanohole... more Specific features of optical second harmonic (SH) generation in arrays of chiral helical nanoholes in a silver film are studied experimentally. An increase in the intensity of the second-order nonlinear optical response is observed in the region of anomalous resonant transmission. The significant role of the rotational symmetry of the array of nanoholes in the formation of the SH response is revealed, which determines the azimuthal dependence of both the intensity of the second-order optical signal and the SH circular dichroism.
Magnetic nanostructures reveal unique interface induced properties that differ from those of bulk... more Magnetic nanostructures reveal unique interface induced properties that differ from those of bulk materials, thus magnetization distributions in interface regions are of high interest. Meanwhile, direct measurement of magnetization distribution in layered nanostructures is a complicated task. Here we study magnetic field induced effects in optical second harmonic generation (SHG) in three-layer ferromagnetic / heavy metals nano films. For a certain experimental geometry, which excludes the appearance of magnetooptical effects for homogeneously magnetized structures, magnetization induced SHG intensity variation is observed. Symmetry analysis of the SHG intensity dependencies on external magnetic field shows that the nonlinear source terms proportional to the out-of-plane gradient component of magnetization govern the observed effect.
A combination of atomic force and confocal microscopy techniques seamlessly assembles and disasse... more A combination of atomic force and confocal microscopy techniques seamlessly assembles and disassembles polymer optical microcavities.
Nonlinear microresonators are very desired for a wide variety of applications. Up-conversion proc... more Nonlinear microresonators are very desired for a wide variety of applications. Up-conversion processes responsible for the transformation of IR laser radiation into visible are intensity-dependent and thus rather sensitive to all involved effects, which can mask each other. In this work we study the phenomena that are the most important for possible lasing in 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4 H-pyran dye spherical microresonators: the two-photon absorption and photobleaching. Based on the suggested model of the threshold-like dependence of the two-photon luminescence (TPL) on pump power, we demonstrate the role of intensity-dependent photobleaching in the appearance of the TPL and find a good agreement with the experiment. This finding is important for the analysis of lasing in nonlinear dye-based resonators.
Journal of Physics: Conference Series, Sep 1, 2018
Organic microstructures attract much attention due to their exciting properties that can be intro... more Organic microstructures attract much attention due to their exciting properties that can be introduced by a proper choice of the composition, shape and alignment in an array. Here we apply the nonlinear optical microscopy for the studies of resonant properties of individual response of organic microspheres of various compositions. The observed spectral modulation of the two-photon luminescence spectra of such structures is caused by excitation of the whispering gallery modes (WGMs) that correspond to the two-photon luminescence spectrum of a particular microparticle specimen. Lasing and photobleaching effects induced by intense near-IR laser radiation are discussed.
Anisotropic metal nanostructures reveal unique optical properties providing new optical effects. ... more Anisotropic metal nanostructures reveal unique optical properties providing new optical effects. Here we study experimentally the nonlinear-optical response of planar arrays of gold comma-like and crescent-like nanostructures made by colloidal lithography. We show that anisotropy of the nonlinear-optical response is defined not only by the shape of the particles, but also by the relative phase of second-order susceptibility components, which are found to be spectrally sensitive. High values of circular dichroism in the second-harmonic generation response up to 70% are observed in comma-like nanostructures.
We discuss photonic effects in arrays of frustum-shaped organic microstructures prepared from org... more We discuss photonic effects in arrays of frustum-shaped organic microstructures prepared from organic orange dye composed on a solid substrate by self-assembling technique. We demonstrate that such structures reveal strong amplification of second-order nonlinear optical response, including optical second harmonic generation (SHG) and two-photon fluorescence (TPF), as compared to that of a continuous film. This is associated with a strong light localization in microstructures composed of high refractive index material. The TPF and SHG power dependencies show that the observed effects are governed by high second-order nonlinearity of the dye damped by a strong absorption. FDTD calculations confirm that the mechanism of the light localization inside organic frustums can be in the form of whispering gallery modes excitation.
2018 International Conference Laser Optics (ICLO), 2018
An experimental technique for measuring the statistics of photocounts for pulsed low-photon light... more An experimental technique for measuring the statistics of photocounts for pulsed low-photon light sources using a SiPM detector is proposed
We study multiphoton processes in optical active organic microrods and microspheres made by self-... more We study multiphoton processes in optical active organic microrods and microspheres made by self-assembly technique which are perspective for possible applications as active waveguides and whispering gallery mode microresonators.
Plasmonic structures are extremely attractive for the light flow manipulation. In turn, the spect... more Plasmonic structures are extremely attractive for the light flow manipulation. In turn, the spectrum of the plasmon excitations can be controlled by external magnetic field, thus giving rise to magnetoplasmonics. However, in the case of traditional magnetoplasmonic structures, the enhancement of magneto-optical (MO) effects is often accompanied by the transmission damp, which constricts the area of their applications. This paper examines resonant optical effects in composite structures based on artificial opal films covered by a thin cobalt layer, which forms a 2D hexagonal lattice of nanoholes in the metal film. Such periodic structure exhibits surface plasmon polariton-assisted extraordinary transmission along with the increase of odd in magnetization intensity magnetooptical effect in the Voigt geometry. Local field enhancement accompanying the surface plasmon polaritons excitation in composite Co/opal structure provides a distinct enhancement of the magnetization-induced second ...
Journal of Experimental and Theoretical Physics, 2020
Specific features of optical second harmonic (SH) generation in arrays of chiral helical nanohole... more Specific features of optical second harmonic (SH) generation in arrays of chiral helical nanoholes in a silver film are studied experimentally. An increase in the intensity of the second-order nonlinear optical response is observed in the region of anomalous resonant transmission. The significant role of the rotational symmetry of the array of nanoholes in the formation of the SH response is revealed, which determines the azimuthal dependence of both the intensity of the second-order optical signal and the SH circular dichroism.
Magnetic nanostructures reveal unique interface induced properties that differ from those of bulk... more Magnetic nanostructures reveal unique interface induced properties that differ from those of bulk materials, thus magnetization distributions in interface regions are of high interest. Meanwhile, direct measurement of magnetization distribution in layered nanostructures is a complicated task. Here we study magnetic field induced effects in optical second harmonic generation (SHG) in three-layer ferromagnetic / heavy metals nano films. For a certain experimental geometry, which excludes the appearance of magnetooptical effects for homogeneously magnetized structures, magnetization induced SHG intensity variation is observed. Symmetry analysis of the SHG intensity dependencies on external magnetic field shows that the nonlinear source terms proportional to the out-of-plane gradient component of magnetization govern the observed effect.
A combination of atomic force and confocal microscopy techniques seamlessly assembles and disasse... more A combination of atomic force and confocal microscopy techniques seamlessly assembles and disassembles polymer optical microcavities.
Nonlinear microresonators are very desired for a wide variety of applications. Up-conversion proc... more Nonlinear microresonators are very desired for a wide variety of applications. Up-conversion processes responsible for the transformation of IR laser radiation into visible are intensity-dependent and thus rather sensitive to all involved effects, which can mask each other. In this work we study the phenomena that are the most important for possible lasing in 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4 H-pyran dye spherical microresonators: the two-photon absorption and photobleaching. Based on the suggested model of the threshold-like dependence of the two-photon luminescence (TPL) on pump power, we demonstrate the role of intensity-dependent photobleaching in the appearance of the TPL and find a good agreement with the experiment. This finding is important for the analysis of lasing in nonlinear dye-based resonators.
Journal of Physics: Conference Series, Sep 1, 2018
Organic microstructures attract much attention due to their exciting properties that can be intro... more Organic microstructures attract much attention due to their exciting properties that can be introduced by a proper choice of the composition, shape and alignment in an array. Here we apply the nonlinear optical microscopy for the studies of resonant properties of individual response of organic microspheres of various compositions. The observed spectral modulation of the two-photon luminescence spectra of such structures is caused by excitation of the whispering gallery modes (WGMs) that correspond to the two-photon luminescence spectrum of a particular microparticle specimen. Lasing and photobleaching effects induced by intense near-IR laser radiation are discussed.
Anisotropic metal nanostructures reveal unique optical properties providing new optical effects. ... more Anisotropic metal nanostructures reveal unique optical properties providing new optical effects. Here we study experimentally the nonlinear-optical response of planar arrays of gold comma-like and crescent-like nanostructures made by colloidal lithography. We show that anisotropy of the nonlinear-optical response is defined not only by the shape of the particles, but also by the relative phase of second-order susceptibility components, which are found to be spectrally sensitive. High values of circular dichroism in the second-harmonic generation response up to 70% are observed in comma-like nanostructures.
We discuss photonic effects in arrays of frustum-shaped organic microstructures prepared from org... more We discuss photonic effects in arrays of frustum-shaped organic microstructures prepared from organic orange dye composed on a solid substrate by self-assembling technique. We demonstrate that such structures reveal strong amplification of second-order nonlinear optical response, including optical second harmonic generation (SHG) and two-photon fluorescence (TPF), as compared to that of a continuous film. This is associated with a strong light localization in microstructures composed of high refractive index material. The TPF and SHG power dependencies show that the observed effects are governed by high second-order nonlinearity of the dye damped by a strong absorption. FDTD calculations confirm that the mechanism of the light localization inside organic frustums can be in the form of whispering gallery modes excitation.
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