This PDF file contains the front matter associated with SPIE Proceedings Volume 11458, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

The dynamics of a semiconductor laser with asymmetric current modulation and injection of external optical radiation is theoretically investigated. An asymmetric modulated laser generates irregular optical pulses both in amplitude and polarization. In this work, it is shown that injection of external optical radiation makes it possible to generate regular sub nanosecond optical pulses. The dependence of the statistical characteristics of the generated pulses on the parameters of the injected radiation is investigated.

Design and preliminary numerical simulations of D-band planar microstrip meander-line slow wave structure for lowvoltage tubes with sheet electron beam were carried out. An original approach based on magnetron sputtering and laser ablation methods was utilized for microstrip meander-line slow wave structure microfarication. An application of nanosecond and picosecond laser ablation for microfabrication of D-band (110-170 GHz) planar microstrip meander-line slow wave structure was considered. We have verified our original approach for planar slow wave structures microfabrication by using different CNC precision laser machines operating with different values of laser pulse duration (100 ns, 8 ns, 4 ns and 10 ps). Samples of slow wave structures were fabricated and characterized by scanning electron microscopy and profilometry methods. It was shown that each considered CNC precision laser machine allows fabricating D-band microstrip meander-line slow wave structure with required dimensions, but picosecond laser ablation has such advantages as the absence of ablation products (droplets, and etc.) on the slow wave structure surface. As the next step, we are going to study S-parameters of microfabricated D-band microstrip meander-line slow wave structure samples experimentally by using vector network analyzer with D-band frequency converters.

In this paper, we consider a short review of existing technologies of flexible antenna fabrication and propose our original approach for flexible antenna fabrication. Review of existing technologies of flexible antenna fabrication includes photolithography, screen printing, pad printing, gravure printing, inkjet printing, micro-dispensing, micro-jetting, and aerosol-jet technology. Advantages and disadvantages of each mentioned above technologies were noted. In the second part of this study, we consider our original technology for antenna fabrication on flexible substrates utilizing magnetron sputtering and laser ablation methods. Samples of flexible antennas are formed on a flexible dielectric substrate in a technology process comprising following basic stages: 1) deposition a conductive coating onto the dielectric substrate with help of magnetron sputtering, 2) formation the pattern of the antenna structure on the conductive coating by laser ablation. In the final stage, the substrate is divided into individual samples of specific sizes. A number of test flexible antennas fabricated by our original approach are shown.

In this study, we address the problem of automated optical trapping using optical tweezers. We demonstrate that using acousto-optical deflector allows implementing a wide variety of specific modes such as multi-trapping and sorting. Our experiments show that this approach enables fast and non-mechanical optical manipulation of microscopic particles according to pre-defined trajectories and tasks.

The light stimulated anomalous self-blocking of all-optical poling process is observed. During investigation the big selfdecrease of light intensity of the generated signals of photo-induced second-harmonic generation has been detected in the region of high values of the induced electric field. The appeared self-decrease of light intensity blocks the process of the writing of the grating of nonlinear second-order susceptibility and leads to the restriction of the maximum value of photo-induced second-harmonic generation. Some properties of the observed phenomenon have been studied and the possible mechanisms of the dynamics of processes are discussed.

Numerical modelling of quantum cascade laser (QCL) is a very complicated problem since the gain is spatially anisotropical in this type of laser. Besides, low efficiency results in very strong thermal effects in CW operation regime. QCL with embedded high index contrast structrures, such as resonant antiguided arrays, can achieve the output power level more than 1W in single spatial mode lasing. We present 3D model of such QCL, which is based on the semivectorial beam propagation method. The single mode operation stability is studied for pulse and CW operation regimes.

The direct measurement of the time parameters of the process of formation of a near-surface laser plasma as a function of the intensity of the laser pulse has been carried out. The quantitative assessment of the durations of various temporal stages characterizing the process of formation of laser plasma in the nanosecond range has been carried out. The threshold intensity of the beginning of the formation of a near-surface laser plasma on a steel target (~70 MW/cm²) and the threshold for the formation of an optically dense plasma (~200 MW/cm²) are quantified. The effect of the selflimitation of the action of a laser pulse during the laser-plasma surface treatment is confirmed. The results can be applied in various laser-plasma technologies: from industrial up to medical.

Gold nanostars are one of the new types of nanoparticles with advantages such as plasmon resonance tunability and low toxicity. Therefore, gold nanostars are promising candidates for various biomedical applications including bioimaging, cell optoporation and plasmonic photothermal therapy (PTT) in NIR I, II, and III optical transparency windows of biotissues. However, the stability and possible transformation of gold nanostars under laser irradiation still remains unexplored. In this work, we studied the photomodification of gold nanostars under the 1064-nm nanosecond pulsed laser irradiation by the transmission electron microscopy and spectrophotometry. The photostability of nanostars depends on their morphology and the plasmonic properties. Specifically, for large nanostars with a plasmon resonance at 950 nm remarkable changes occur at a threshold pulse energy of 5 μJ. At this threshold, a significant part of nanostars spikes melts and most of the nanostars start to transform into gold spheres. For higher pulse energies of about 50 μJ, all stars transform into spheres. For smaller gold stars with a plasmon resonance at 680 nm, the changes are less pronounced. Up to pulse energy of 50 μJ, they retain the shape of stars and have spikes on their surface. Moreover, the complete transformation of these stars into spheres does not occur up to pulse energy of about 150 μJ. The obtained results can be important for optimization of PTT treatment with gold nanostars and nanosecond laser irradiation.

In this paper, we address quantitative phase imaging of hard-to-reach objects using conventional endoscopic probes. We present a scheme of digital holographic module compatible with commercially available rigid rod-lens endoscopes. In this scheme, a reference beam is obtained using a single-mode optical fiber. The module is a quite simple two-lens system located behind the endoscope eyepiece. It allows the registration of Fourier holograms as well as conventional imaging mode.

We investigate laser trapping of airborne light-absorbing particles via photophoretic forces. It is well known that the use of photophoretic forces allows one to guide light-absorbing nano- and microparticles at distances of up to tens of centimeters. We use various types of structured laser beams (optical "bottle" beams and line-shaped optical traps) for manipulation of agglomerations of carbon nanoparticles. The possibility to trap and guide both single light-absorbing particles and arrays of light-absorbing particles is demonstrated. In addition, the possibility of power-dependent particle guiding is shown.

The article presents experimental results on charging free-falling particles of titanium dust about 40 microns in size using femtosecond laser pulses, as well as comparing the results with earlier studies on particle charging by nanosecond laser pulses. The results include the ratio of the achieved charge of dust particles under various conditions: beam size, energy, and laser pulse duration. The problems of multiphoton ionization, the degree of nonlinear process, and the quantum efficiency of femtosecond charging are discussed.

A method for measuring acceleration based on the use of the fast-discrete Fourier transform algorithm is proposed. The simulation of the spectrum of the self-mixing signal at the uniformly accelerated motion of the reflector is carried out. The relationship of low-frequency and high-frequency components of the self-mixing signal spectrum with the object acceleration value is shown. The measurement of uniformly accelerated motion of an object on the spectrum of a self-mixing signal is experimentally realized. The accelerated motion of the reflector was carried out using a signal generator built into the laboratory station of the Ni ELVIS virtual instruments. The results of measuring the motion of piezoceramics with the acceleration given by the quadratic law of voltage change on it are presented. The results of calculation of acceleration on the spectrum of the self-mixing signal for 26 μm/s² are presented. The resolution of the proposed method was estimated by measuring the frequencies of neighboring spectral components and amounted to 500 nm/s².

In this paper, we study the examples of sapphire capillary needles for interstitial laser thermotherapy and photodynamic therapy. Such needles are fabricated by means of the Edge-defined Film-fed Growth (EFG) technology, so that they feature an as-grown optical quality. The optical fiber, which is used for delivering laser radiation to tissue, is placed inside the capillary channel in the needle's body. The channel is closed at the one side, therefore, the fiber is protected from the direct contact with biological tissue. The needle's tip form plays a significant role in the formation of the particular radiation pattern and the corresponding volume of treatment. Using a tissue phantom, we have experimentally studied the radiation distribution formed by sapphire needles with different tip angle. The results demonstrate rather smooth spatial distribution of light, confirming the high surface quality of the needles and the ability to control the amount of exposed tissue by changing the tip angle.

Waves propagating in a bianisotropic medium with absorption are generally polarized along orthogonal ellipses, special cases are waves of s- and p-polarizations, as well as waves of two circular polarizations. The report presents the transformation of the reflection and transmission matrices when the basis waves change: from a basis of s- and ppolarizations to a basis of right and left circular polarization and to a basis of two orthogonal elliptic polarizations.

The results of a theoretical investigation of the evolution of a probe pulse under electromagnetically induced transparency in the Λ -scheme of degenerated inhomogeneously broadened quantum transitions are presented. It supposed that the interacted light fields are elliptically polarized, and their influence on the medium can be either strictly resonant or quasiresonant. It is demonstrated that the probe pulse in the medium can be presented as the sum of two normal modes, i.e. quasi-monochromatic elliptically polarized fields propagating independently of each other. Due to the fact that velocities of normal mode pulses are different, a single probe pulse entering a medium splits into individual pulses inside of the medium, each of which transfers the energy of one of the normal modes. If normal modes are not phase modulated at the input surface, then in the case of quasi-resonance they become phase modulated during propagation in the medium, whereas this does not occur in the case of strict resonance. The total probe field, which is the sum of normal modes, has phase modulation before it splits into the mode pulses in cases of both strict resonance and quasi-resonance, even if it does not have it on the input surface.

The study of an influence of the different chemical components on process of the nonlinear generation of light harmonics in various isotropic glasses, polymer and composite materials attracts an attention of scientists in connection with a possibility of future development of new high effective broadband optical elements for micro- and nano-optoelectronics. In this paper the effect of lead oxide concentration on the generation of light harmonics in different optical glass media is analyzed. The attention of investigation is focused on the detailed comparison of the results of study of the writing times, relaxation processes and the potential efficiencies of the nonlinear generation of light harmonic in various composite samples.

We consider the oblique incidence of optical pulses of a special shape: triangular, Gaussian, meander, and also a giant laser pulse onto a flat anisotropic inhomogeneous structure with dispersion. The electromagnetic wave has an elliptical polarization; the direction of the optical axis of the anisotropic uniaxial medium changes with distance from the interface. The change in the shape of the envelopes of pulses of ordinary and extraordinary waves is presented during propagation in an anisotropic inhomogeneous medium with dispersion.

We experimentally investigate a novel type of diffractive optical element – a nonlinear spiral phase plate. In contrast to the conventional spiral phase plates, the transmission function of the new element is described as exp(imφⁿ ). The intensity distributions generated by these elements have a spiral shape with an intensity gradient. The phase distribution of the generated light fields is also spiral shaped. We believe that the proposed diffractive element will be useful in the area of laser manipulation and laser–matter interaction.

In this paper, we have investigated the entanglement dynamics between two identical two-level atoms in the framework of two-photon double Jaynes-Cummings model taking into account the detuning between atoms and twice cavities frequencies and Kerr nonlinearities in both cavities. We have carried out the temporal dependence of the atom-atom negativity for Bell’s initial entangled atomic states. The results show that these parameters have great impact on the amplitudes of the atom-atom entanglement oscillations and that presence of detuning and Kerr nonlinearity lead to stabilization of entanglement for all Bell-types initial atomic states. For a certain initial atomic entangled states, there is an entanglement sudden death effect between the two atoms. The detuning and Kerr medium in the cavities can prevent the undesirable entanglement sudden death from occurring.

In this paper, we have investigated the entanglement dynamics between two initially entangled qubits interacting with two independent thermal cavities modes in the framework of resonant double Jaynes-Cummings model. We obtain the exact solution for the model under consideration and derive the time dependence of the atom-atom negativity. Results reveal that for entangled atoms the initial atomic quantum correlations can partially restore its original values for a finite interval of time, even for relatively high cavity temperatures.

A new approach to the interpretation of OCT probes of coarse-grained random media is considered. In the framework of the approach, the integrated scan-depth-dependent diffuse reflectivity of a probed sample is estimated using a set of OCT A-scans. A relationship between the integrated reflectivity and a transport mean free path of light propagation in the probed sample is established using Monte-Carlo simulations. The considered technique was applied for characterization of the structure of highly porous polymer (polylactide) matrices synthesized using a supercritical fluidic (SCF) foaming of a pre-plasticized raw polymer. The results of experimental verification of the considered technique are compared with similar data obtained in the framework of other approaches to OCT data interpretation.

The results of investigation of the magneto-optical effects of Faraday and Cotton-Mouton in organic liquids are presented. It is shown that the polarization characteristics of radiation change when it pass through benzene, toluene, kerosene and petrol of several grades. The rotation of the plane of polarization occurs when the direction of induction of the magnetic field along the direction of propagation of light. Linearly polarized light acquires ellipticity when radiation propagates perpendicular to the direction of magnetic field induction. The Faraday and Cotton-Mouton constants of the substances have been determined for radiation with wavelengths of 650 nm, 532 nm and 405 nm.

The paper presents the results of investigation into the randomly inhomogeneous dye-doped media using the referencefree low-coherence reflectometry method under conditions of low spectral selectivity of the system for the detecting fluorescence radiation scattered by the medium. An increase in the width of the spectral window of the detector leads to substantial suppression of spatial fluctuations in fluorescence intensity excited by the probing laser beam. The optically thick layers of close-packed titanium dioxide nanoparticles saturated with an aqueous solution of rhodamine 6G were used as the media under investigation. It should be noted that the obtained dispersion dependence of the oscillation index of spatial intensity fluctuations on the central wavelength of spectrally selectable fluorescence radiation agrees with the previously received characteristic features of the fluorescence radiation transfer in the similar systems. These results demonstrate a possibility for using spectrometric systems with relatively low resolution (with the spectral window width of the order of 1 nm) to implement the method of reference-free low coherence reflectometry of the randomly inhomogeneous media.

The paper presents the results of a study of photoinduced disturbances in the operation of polarizing optical devices based on a lithium niobate crystal.. Significant changes were found in the modulation dependences of the electro-optical modulator with increasing intensity and time of irradiation. The intensities of photoinduced electric fields and changes in the electro-optical coefficients of the crystal are determined.

The computational scheme and calculation results of bound, metastable and Rydberg states of atomic and molecular systems important for laser spectroscopy are presented. The solution to the problem is performed using the authors' software package (see program libraries of the Computer Physics Communications journal and of the Joint Institute for Nuclear Research) that implement the high-accuracy finite element method. The FORTRAN procedure of matching tabulated potential functions with van der Waals asymptotic potential using interpolation Hermite polynomials which provides continuity of both the function itself and its derivative is presented. The efficiency of the proposed approach is demonstrated by calculated for the first time sharp metastable states with complex eigen-energies in a diatomic beryllium molecule and weakly bound Rydberg states of antiprotonic helium atom.

For many methods of optical spectroscopy, there is no analytical and/or direct numerical solution for the problem of determination of concentrations of each component in multi-component solutions by spectra. Therefore, recently, the application of machine learning methods to solve these problems has been actively investigated. In this study, it is suggested to use an ensemble of optical spectroscopy methods to increase the accuracy and noise resilience of the solution obtained by machine learning methods. We consider joint use of Raman spectroscopy and optical absorption spectroscopy methods to determine the concentrations of heavy metal ions in water. This complex inverse problem is solved by artificial neural networks as a machine learning method. It is demonstrated that when one of the methods is strong by its results, and the other is weak, their joint application does not allow one to improve the results of the strong method. Some other observations regarding the solution of the studied problem are reported.

The paper discusses the use of a laser wave of elliptical and circular polarization under ATR conditions. It is shown that when a wave of right circular polarization is incident on an object under study, a change in the nature of polarization occurs when scanning the angle of incidence — from the right elliptical, through the linear to the left elliptical. The analysis of the parameters of the ellipse and ellipsometric parameters during the incidence of a circularly polarized wave on a layered prism-metal-air and prism-metal-bioobject-air structure according to the Kretschman scheme under the condition of excitation of surface plasmons is carried out. For the first time, the characteristic shifts between the minima of the eliipsometric parameters and the parameters of the ellipse of polarization of reflected light, carrying information about the object under study, were calculated. It is also shown for the first time that for these parameters the maxima of the ellipsometry parameter and the ellipse parameter shift, which is responsible for the eccentricity and direction of rotation of the field vector along the polarization ellipse. The results obtained expand the scope of plasmon resonance spectroscopy to the more general case of elliptically polarized light.

The structural parameters and vibrational IR and Raman spectra of the molecular unit of the chitosan polymer, chitosan dimer, and chitosan dimer in complex with SWCN fragment were calculated. It is shown that the interaction of the chitosan dimer with SWCNTs leads to a change in the valence angle of the COS linking the elementary units of the chitosan biopolymer and the valence angle of the hydrogen bond bridge C ... .NO. In the IR spectra, an increase in the intensity of the absorption bands in the region of ~1000 cm^-1 is observed, and in the Raman spectra – an increase in the intensity of the lines in the low-frequency region of ~400-600 cm^-1.

The calculation and interpretation of the IR of three Proline (Pro) conformers were performed. It is shown that the vibrational spectrum of Pro in the gas phase is a superposition of the vibrational spectra of conformers Pro 1 (60%) and Pro 2 (40%). The calculated total IR spectrum is in good agreement with the experimental Pro spectrum recorded at 520 K.

The paper presents the results of an experimental study of the role of the Fermi resonance (FR) between the overtone of the bending and symmetric valence vibrations of the water molecule in micellar solutions of sodium octanoate in the mechanisms of formation of the water valence band. The analysis of broad spectral bands was carried out using genetic algorithms and gradient methods. The frequency detuning between the components of the Fermidoublet for all the samples were obtained at room temperature. For aqueous solutions of sodium octanoate in the critical concentration of micelle formation (0.4 M) frequency detuning ceases to decrease with the growth of surfactant concentration, which is explained by the strengthening of the network of hydrogen bonds in the solution in the process of combining monomers and dimers of surfactants in multimolecular aggregates - micelles. A significant contribution of the Fermi resonance to the intensity of the valence band of water in sodium octanoate solutions was demonstrated. The FR interaction constants were calculated.

The influence of structure of the phosphine oxide ligands on stability of their complexes was studied by spectroscopic techniques. Surprising the electron donating methyl groups at phenyl rings of phosphine oxide groups lead to decrease of the stability of europium complex comparing with ubsubsituted one due to their sterical prevention of conjugation between phenyl rings and P=O-groups.. This unusual behavior was first time demonstrated by spectroscopic titration and Job’s plot analysis.

Deceleration of terahertz plasma waves (plasmons) in tapered graphene-insulator-graphene heterostructure is studied. It is shown that the plasmon energy velocity can become several times smaller as compared to that near the taper apex.

The numerical investigation of difference frequency generation in a system of two-wavelength semiconductor lasers with a vertical external resonator is presented. Maps of dynamic regimes on the plane of parameters “pump power - delay time in the external resonator" are constructed. The regions of continuous wave, periodic oscillations, as well as quasiperiodic and chaotic oscillations of the radiation intensity are distinguished. The existence of stable periodic motions of the system can be explained in terms of the concept of synchronizing the frequency of normal modes with the frequency of intermode beats.

In this paper, new structural types of vertical heterostructures based on monolayers of semiconductor and dielectric 2D graphene-like materials are proposed. Using computer modeling methods, it is found that monolayers of borophane, blue phosphorus and gallium nitride can be used to form bilayer and three-layer vertical heterostructures of the following type: gallium nitride/borophane and gallium nitride/blue phosphorus bilayer structures, as well as gallium nitride/blue phosphorus/gallium nitride three-layer structures. It is shown that the constructed atomistic models of vertical heterostructures are energetically stable configurations. It was revealed that the proposed types of vertical heterostructures are characterized by the presence of an energy gap from 0.5 to 1.3 eV in size, which indicates their semiconductor properties.

We consider the results of dielectric properties study in millimeter band of thin-films based on silicon nitride compositions. Silicon nitride thin-film coatings were deposited on a substrate by DC magnetron sputtering. As a substrate for silicon nitride thin-film coatings a quartz plate were utilized. The ratio of argon and nitrogen in the working gas mixture was chosen as the variable parameter to control the composition of the deposited thin-film coating. Several samples of silicon nitride thin-film coatings with about 1 um thickness were fabricated. Radiophysical and dielectric properties of the fabricated SiN-type thin-film coatings were studied in millimeter wave frequency band of 50-70 GHz (V-band) with help of free space measurement method. The obtained results have shown that by controlling the resistive thin-film coating composition one can only slightly vary the radiophysical and dielectric properties of coating in millimeter-band.

In this paper we developed the model of GHz- and THz-waves detector on the base of single-walled carbon nanotube functionalized with trimer of fullerene C₆₀ and free fullerenes C₃₆ and C₈₀. It was discovered the amplitude of internal fullerenes’ oscillation depends on temperature and strength of electromagnetic wave. It was found the parameters of incident wave when fullerene C₃₆ and C₈₀ reach wall of carbon nanotube at the distance of 1.7 Å that is not sufficient to form covalent bonds. At such regime fullerenes accept charge from carbon nanotube that leads to change of system’s IV-curve. Discovered phenomena can be the basis for design of nanodetector.

The DC conductivity of thin random layers of anatase nanospheroids deposited onto the insulating substrates with interdigital electrode systems was experimentally studied using pulse-periodic laser irradiation near the edge of the fundamental absorption band of anatase. Evaluation of the conductivity slew rate at the beginning of laser irradiation depending on the laser wavelength was used for estimation of the Urbach energy of the examined system at various temperatures. Obtained results are compared with the previously reported data relating the Urbach energy of the densely packed ensembles of anatase nanotubes at room temperature.

We consider the plasmon-polaritons along a layer of hyperbolic metamaterial propagating in the plane of the anisotropy axis with an arbitrary its orientation. As a layer material, we use periodic plane-layered artificial medium – hyperbolic metamaterial of thin metal and dielectric layers and produce its homogenization. The conditions for the existence of fast, slow, leakage, gliding flowing, forward and backward plasmon-polaritons are found. The Fresnel formulas for the diffraction of a plane wave of arbitrary polarization on such a structure are obtained. The dispersion of plasmonpolaritons and plane wave diffraction are calculated. It is proposed to use a strong magnetic field to control dispersion and scattering.

We consider the photon tunneling through the structure with bang gap formed from layers with negative dielectric permittivity or from transparent layers, supporting due to the periodicity of the barrier the band with a low coefficient of transparency. The rate of energy transfer in such structure and the time of its transfer are investigated. It is shown that in all cases the rate of energy transfer does not exceed the speed of light. Therefore, the known paradoxes using BohmWigner time of the Hartmann paradox type are precisely paradoxes, i.e. the false statements.