Zn1-xMgxSe: A PROMISING MATERIAL FOR NON-LINEAR OPTICS

A theoretical analysis of the condition of scalar phase-matched second harmonic generation and optical parametric oscillation (OPO) in single-crystalline samples Zn0.52Mg0.48Se is presented. The calculated range of pumping for second harmonic generation with phase matching is 5.1-13 μm. The tuning range of the optical parametric oscillator based on Zn0.52Mg0.48Se is determined. The combination of active media and nonlinear converter for OPO in the same optical element are proposed.

CHAOTIC DYNAMICS OF A NONLINEAR ELECTRONIC CONVERTER

The nonlinear electronic converter used by Rulkov and collaborators [Rulkov et al., 2001], which is the core of their chaotic oscillator, is modeled and simulated numerically by means of an appropriate direct relationship between the experimental values of the electronic components of the system and the mathematical model. This relationship allows us to analyze the chaotic behavior of the model in terms of a particular bifurcation parameter k. Varying the parameter k, quantitative results of the dynamics of the numerical system are presented, which are found to be in good agreement with the experimental measurements that we performed as well. Moreover, we show that this nonlinear converter belongs to a class of 3-D systems that can be mapped to the unfolded Chua's circuit. We also report a wavelet transform analysis of the experimental and numerical chaotic time series data of this chaotic system. The wavelet analysis provides us with information on such systems in terms of the concentration of energy which is the standard electromagnetic interpretation of the L2 norm of a given signal.

Displacement Measurement, Nonlinearity, Noise, and Thermal Stability

Nonlinear distortions, noise, and thermal instability are the most important error sources of non-contact displacement and distance measurement. In this work, the ways of elimination of these errors are considered. Two methods are proposed and analyzed. The first method helps to exclude nonlinear distortions and noise. According to this method, the nonlinear converter is driven to harmonic oscillations orthogonally to the object surface with constant amplitude. Fourier coefficients are calculated for the different node positions of the vibrating converter. Calibration curve of the converter is reconstructed from collections of derivatives, which are obtained solving system of linear equations. The second method uses ratio of the two Fourier coefficients as the informative parameter and helps to exclude thermal instability. In this paper, there is shown that when the method is more noise resistant it is less thermally stable, and vice versa.