Stochastic model for the epitaxial growth of two-dimensional islands in the submonolayer regime

The diffusion-based growth of islands composed of clusters of metal atoms on a substrate is considered in the aggregation regime. A stochastic approach is proposed to describe the dynamics of island growth based on a Langevin equation with multiplicative noise. The distribution of island sizes, obtained as a solution of the corresponding Fokker-Planck equation, is derived. The time-dependence of island growth on its fractal dimension is analysed. The effect of mobility of the small islands on the growth of large islands is considered. Numerical simulations are in a good agreement with theoretical results

Predator population depending on lemming cycles

In this paper, a Langevin equation for predator population with multiplicative correlated noise is analyzed. The noise source, which is a nonnegative random pulse noise with regulated periodicity, corresponds to the prey population cycling. The increase of periodicity of noise affects the average predator density at the stationary state

The trend in the development of a system that combines the placement and use of tangible assets such as warehouses, terminals, and storage facilities of enterprises

The article discusses the idea of creating an Internet resource in order to combine the needs and offers of services for storage, transportation, rental of warehouses, premises, open storage areas, etc. in the Tomsk region

Numerical simulation of multi-color laser generation in TM-doped tellurite microsphere at 1.9, 1.5 and 2.3 microns

We present the first detailed theoretical analysis of multi-color continuous wave lasing in Tm-doped tellurite spherical microresonators with whispering gallery modes pumped at a wavelength of 792 nm. The numerical model is based on solving a system of equations for intracavity field amplitudes and rate equations using the parameters of Tm-doped tellurite glass measured in the previous experiments. All fundamental whispering gallery modes in the gain bands are taken into account. We demonstrate diagrams of generation regimes depending on Q-factors and pump power, which show a possibility of single-color lasing at a wavelength of similar to 1.9 mu m, two-color lasing at wavelengths of similar to 1.9&1.5 mu m and at similar to 1.9&2.3 mu m, and three-color lasing at wavelengths of similar to 1.9&1.5&2.3 mu m. Such microlasers can play a significant role in sensing applications

Quantum noise squeezing of CW light in tellurite glass fibres

Light with suppressed quantum fluctuations is desirable for a lot of applications. There are several approaches to suppress a noise including Kerr squeezing in optical fibres. Silica fibres are commonly used for this purpose. Here we propose to use highly nonlinear tellurite glass fibres for Kerr squeezing of CW laser field and demonstrate by simulations in the framework of the stochastic generalized nonlinear Schrodinger equation the possibility of -20 dB noise suppression. In simulations, Raman terms and losses are switched on and switched off to find their contributions to the limits of squeezing. The analytical estimates without loss and with lumped loss are also given

Single-shot reconstruction of a subpicosecond pulse from a fiber laser system via processing strongly self-phase modulated spectra

The single-shot reconstruction of an ultrashort pulse from a fiber laser system by the method based on recording and numerical processing of two self-phase modulated spectra after a nonlinear fiber is demonstrated experimentally. The 0.7-ps asymmetrical signal with an energy of similar to 1 mu J retrieved by this method without time direction ambiguity is in good agreement with independent measurements by second harmonic generation frequency-resolved optical gating (SHG FROG) technique

Lenslet array-free efficient coherent combining of broadband pulses at the output of a multicore fiber with a square core grid

An efficient optical scheme for coherent combining of radiation from the output of a multicore fiber (MCF) with a square array of cores in the out-of-phase supermode is proposed. The scheme uses only simple optical elements and is suitable for an arbitrary number of MCF cores. In a proof-of-concept experiment broadband pulses transmitted through a 25-core fiber were combined with 81% efficiency and good beam quality. In numerical modeling a close to unity efficiency is obtained for a large number of cores. The proposed scheme can be used in a reverse direction for efficient beam splitting and launching the out-of-phase supermode into the MCF. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreemen