A comprehensive approach for non-contact, non-destructive, and high-precision analysis of surface inhomogeneity distributions has been proposed, enabling reconstruction of the surface height distribution with coefficients of determination (R2) ranging from 0.86 to 0.90, based on the photoluminescence intensity distribution of surface-deposited perovskite nanoparticles. Perovskite nanoparticles of about 5 nm were employed as functional markers, reproducing the surface topographic profile after deposition. A machine learning model based on graph convolutional networks (GCN) was developed to analyze and reconstruct the height distribution of surfaces with nano-and micro-inhomogeneities. The model was trained using experimental data obtained by atomic force microscopy to determine the surface height profile, together with measurements of the luminescence intensity of the deposited nanoparticles.
Transmission symmetry breaking is important for realizing direction-selective light transport in integrated photonics, while existing approaches generally rely on magneto-optical materials, temporal modulation, or strong optical nonlinearities. We theoretically investigate thermal-feedback-induced transmission symmetry breaking in an asymmetric Fabry-P & eacute;rot microcavity filled with polydimethylsiloxane. Due to unequal mirror reflectivities, counterpropagating optical fields exhibit different coupling efficiencies and absorption powers, resulting in distinct thermally induced resonance shifts and transmission characteristics. Numerical results show that the proposed nonmagnetic structure can achieve a transmission contrast exceeding 50 dB. The proposed mechanism provides a simple approach for realizing compact integrated photonic devices with direction-selective transmission.
This work presents a comprehensive analytical investigation of stochastic optical solitons propagating in highly dispersive birefringent fibers governed by Kerr-law refractive-index nonlinearity in the It & ocirc; sense. Starting from a coupled stochastic nonlinear Schr & ouml;dinger system including high-order dispersion, cross-phase modulation, and Wiener-induced phase fluctuations, a traveling-wave reduction is employed to obtain a deterministic ordinary differential equation for the soliton envelopes after imposing appropriate constraint conditions. Using the modified subsidiary ordinary differential equation sub-ODE method, we derive several families of exact closed-form solutions, including bright, dark, singular, and Weierstrass elliptic structures, together with their corresponding existence conditions. The bright and dark soliton solutions are subsequently analyzed to illustrate the effects of stochastic perturbation. The analytical results reveal how the hierarchy of higher-order dispersion interacts with Kerr nonlinearity to stabilize localized waveforms, while the It & ocirc; stochastic term modifies only the internal phase without affecting the soliton modulus. Furthermore, the obtained soliton families satisfy the derived stability conditions, demonstrating that the envelope profiles remain robust despite the presence of multiplicative white noise. These findings provide new insight into noise-driven nonlinear wave propagation in birefringent optical fibers and offer exact analytical benchmarks for ultrafast photonics, nonlinear pulse management, and stochastic optical systems.
Pb1-xEuxTe (x=0.1) thin films with a thickness of 1.5-2 mu m were grown on glass and mica substrates by molecular beam condensation. X-ray diffraction revealed that the films crystallize mainly in the cubic PbTe phase with the Fm(-)3 space group, accompanied by a weak Eu-rich secondary phase with the Pm(-)3 space group. The substrate type strongly influenced the preferred orientation, with (200) texture observed on glass and (222) orientation on mica. Room-temperature photoluminescence measurements revealed pronounced infrared emission with three overlapping components centered at approximately 1779, 1811, and 1872 nm (0.697, 0.685, and 0.662 eV, respectively). The two higher-energy components are close to the similar to 0.70 eV band-gap value calculated for the Pb0.875Eu0.125Te (x=0.125) model, whereas the lower-energy component extends into the sub-gap region. The observed emission is consistent with contributions from electronic states near the band edges and an additional lower-energy radiative channel, although room-temperature PL alone cannot unambiguously assign the individual emission mechanisms
