Fabry-Perot Bound States in the Continuum in an Anisotropic Photonic Crystal

An anisotropic photonic crystal containing two anisotropic defect layers is considered. It is demonstrated that the system under can support a Fabry-Perot bound state in the continuum (FP-BIC). A fully analytic solution of the scattering problem as well as a condition for FP-BIC have been derived in the framework of the temporal coupled-mode theory

Enhanced light absorption in Tamm metasurface with a bound state in the continuum

We consider light absorption in a germanium grating placed on top of photonic-crystalline substrate. Such a system supports an optical Tamm state decoupled from the continuous spectrum with its frequency within the photonic band gap. We have demonstrated that application of the Tamm state makes in possible to engineer extremely narrow absorber which provides a 100% absorption in a semiconductor grating in the critical coupling regime. The proposed design may be used at both normal and oblique incidence at the telecom wavelength

Hinton, Deane R.

The chiral optical Tamm state (COTS) is a special localized state at the interface of a handedness-preserving mirror and a structurally chiral medium such as a cholesteric liquid crystal or a chiral sculptured thin film. The spectral behavior of COTS, observed as reflection resonances, is described by the temporal coupled-mode theory. Mode coupling is different for two circular light polarizations because COTS has a helix structure replicating that of the cholesteric. The mode coupling for co-handed circularly polarized light exponentially attenuates with the cholesteric layer thickness since the COTS frequency falls into the stop band. Cross-handed circularly polarized light freely goes through the cholesteric layer and can excite COTS when reflected from the handedness-preserving mirror. The coupling in this case is proportional to anisotropy of the cholesteric and theoretically it is only anisotropy of magnetic permittivity that can ultimately cancel this coupling. These two couplings being equal results in a polarization crossover (the Kopp--Genack effect) for which a linear polarization is optimal to excite COTS. The corresponding cholesteric thickness and scattering matrix for COTS are generally described by simple expressions

Мінімізація опору персоналу організаційним змінам на підприємстві

Обґрунтовано підходи до мінімізації опору персоналу організаційним змінам на підприємстві. На основі аналізу недоліків існуючих підходів запропоновано концептуальні положення мінімізації опору персоналу організаційним змінам на підприємствах, у рамках реалізації яких розроблено підхід до оцінки рівня підтримки організаційних змін у колективі після інформаційної взаємодії між співробітниками та підхід до прийняття рішень у сфері управління мінімізацією опору персоналу організаційним змінам на підприємстві, що базується на оптимізаційній моделі вибору оптимальних рішень. Здійснено практичну апробацію запропонованих підходів на діючому промисловому підприємстві та сформульовано перспективи подальших досліджень.Обоснованы подходы к минимизации сопротивления персонала организационным изменениям на предприятии. На основе анализа недостатков существующих подходов предложены концептуальные положения минимизации сопротивления персонала организационным изменениям на предприятиях, в рамках реализации которых разработаны подход к оценке уровня поддержки организационных изменений в коллективе после информационного взаимодействия между сотрудниками и подход к принятию решений в сфере управления минимизацией сопротивления персонала организационным изменениям на предприятии, базирующийся на оптимизационной модели выбора оптимальных решений. Осуществлена практическая апробация предложенных подходов на действующем промышленном предприятии и сформулированы перспективы дальнейших исследований.The article is devoted to substantiating the approaches to minimizing the resistance of staff to organizational changes at an enterprise. It was revealed that existing scientific approaches do not allow formalizing the assessment of organizational resistance and minimizing the costs of preventing organizational resistance; they do not take into account such important factors as the authority of the members of the staff, objective benefits of a decision for the staff members and their inclination to adopt other people’s opinions. They do not allow assessing the staff members support for organizational change taking into account the information interaction between them. Based on the analysis of the shortcomings of existing approaches conceptual positions to minimizing the resistance of staff to organizational changes at enterprises were proposed, as part of which an approach was developed to assessing the level of support for organizational changes by the staff after the information interaction between the staff members, as well as an approach to managing the minimization of staff resistance to organizational changes at an enterprise based on the optimization model of optimal (in terms of cost and results) decisions. In terms of decision-making, the main task is the choice of optimal measures (interventions) that work through changing the objective benefits of the decisions and the initial level of support. A practical approbation of the proposed approaches at an existing industrial enterprise was carried out, and perspectives for further research were formulated. Prospects for further research are in the development of tools for minimizing organizational resistance and developing methods for assessing the characteristics of workers

Tunable hybrid Tamm-microcavity states

Spectral manifestations of hybrid Tamm-microcavity modes in a 1D photonic crystal bounded with a silver layer and containing a nematic liquid crystal microcavity layer have been studied using numerical simulation. It is demonstrated that the hybrid modes can be effectively tuned owing to the high sensitivity of the liquid crystal to the temperature and external electric field variations. It is established that the effect of temperature on the transmission spectrum of the investigated structure is most pronounced at the point of the phase transition of the liquid crystal to the isotropic state, where the refractive index jump is observed

Quasiperiodic one-dimensional photonic crystals with adjustable multiple photonic band gaps

We propose an elegant approach to produce photonic band gap structures with multiple photonic band gaps (PBGs) by constructing quasiperiodic photonic crystals (QPPCs) composed by a superposition of photonic lattices with different periods. Generally QPPC structures exhibit both aperiodicity and multiple PBGs due to their long-range order. They are described by a simple analytical expression instead of quasiperiodic tiling approaches based on substitution rules. Here we describe the optical properties of quasiperiodic photonic crystals exhibiting two PBGs that can be tuned independently. PBG interband spacing and their depths can be varied by choosing appropriate reciprocal lattice vectors and their amplitudes. These effects are confirmed by the proof- of-concept measurements made for the porous silicon based QPPC of the appropriate design