Within the framework of the effective-mass approximation, the effect of different static perturbations—lateral electric field, impurity donor, and eccentricity distortion—on the nonlinear optical rectification in a GaAs disc-shaped quantum ring has been investigated. For a concentric ring, the influence of the lateral electric field and off-center impurities on the intraband transitions at two values of temperature was studied in detail. We found that the optical response strongly depends on the incident light polarization and donor position within the structure. Compared with the profile at 4 K, the optical rectification spectra exhibit at 77 K additional peaks of reduced magnitude in the low-frequency range. The main transition peaks become smaller, while their positions remain almost unchanged with temperature. For eccentric structures, relevant differences between small and large eccentricity regimes can be observed in the electronic properties. In this case, the energy spectra and the nonlinear optical response are very sensitive to the direction of the applied electric field. The effect can be used to identify the eccentricity of the system.

The paper presents applications of the recurrence plot quantification to the analysis of type 1 intermittency observed in a discharge plasma. The main measures of recurrence plot analysis considered are the laminarity and the determinism. First, it is demonstrated that the laminarity measure can be related to the average time between chaotic bursts in this type of intermittency. Second, it is shown that the determinism measure introduced by the recurrence plot quantification depends on the control parameter as a decreasing exponential. The test of the results is performed by analyzing the determinism measure for type 1 intermittency observed in the logistic map. It is also shown that the role of the intrinsic noise of the plasma can easily be identified by this technique.

Trapping of microparticles and aerosols is of great interest for physics and chemistry. We report microparticle trapping in case of multipole linear Paul trap geometries, operating under standard ambient temperature and pressure conditions. An 8- and 12-electrode linear trap geometries have been designed and tested with an aim to achieve trapping for larger number of particles and to study microparticle dynamical stability in electrodynamic fields. We report emergence of planar and volume ordered structures of microparticles, depending on the a.c. trapping frequency and particle specific charge ratio. The electric potential within the trap is mapped using the electrolytic tank method. Particle dynamics is simulated using a stochastic Langevin equation. We emphasize extended regions of stable trapping with respect to quadrupole traps, as well as good agreement between experiment and numerical simulations.