Journal of Nonlinear Optical Physics & Materials

In this paper, a sixth-order nonlinear partial differential equation which can be used to describe the propagation pulse in optical fibers is studied by using the methods of trial equation and complete discrimination system for polynomial. We have obtained some exact optical wave solutions, including singular solutions, solitary wave solutions, and elliptic function double periodic solutions, which can be completely classified in parameter space.

Multi-branched oligomers F1, F2 and F3 were investigated by spectroscopic experiments as well as quantum chemical calculations to elucidate the structure–property relationships and intramolecular charge transfer (ICT) characteristics of typical nonlinear optical materials. A better ICT property of F2 is obtained by replacing terminal electron donors with stronger electron-donating ability. The degree of ICT is effectively increased, which can be clearly seen from the frontier molecular orbitals contribution of central anthracene between HOMO and LUMO. The central group plays a major role in the direction as well as effective path of ICT process. In the X-shaped oligomers with anthracene as central group, ICT process takes place from terminal groups of 1,8 position branches, to the central anthracene group. However, the electron distribution as well as the ICT of tri-branched oligomer F3 with triazine as central group is not symmetric. ICT process of F3 takes place from terminal triphenylamine groups to the central triazine and two fluorene groups at 4,6 position branches. Y-shaped oligomer F3 has a longer lifetime of ICT state as well as a higher fluorescence quantum yield, which is consistent with the results of time-resolved fluorescence spectroscopy. Z-scan results show that the TPA cross-section value of F3 is 10.6 and 2.9 times higher than that of X-shaped F1 and F2. The dynamics curves of transient absorption spectroscopy also indicate that oligomer F3 structure has relatively stronger ICT properties. To verify the substituent effect, two linear molecules F4 and F5 were also calculated. The quantum chemical calculations result shows that the branches at positions 4 and 11 of the central anthracene group have little effect on the electron cloud distribution, and there are indeed significant differences in the contributions of branches at different positions. Our results may provide some reference for molecular design.

The second-order optical nonlinearity (SON) of thermally poled fused silica was shown for the first time to be significantly improved by the implantation of multi-energy boron (B) ions, and the outcomes were compared with those obtained from the implantation of multi-energy argon (Ar) ions. Second-harmonic (SH) signals in both samples grew roughly linearly as the poling temperature rose. Samples with Ar implants showed a greater increase in SH signal with rising poling temperature. A qualitative explanation for the formation of ${\chi }^{(2)}$ in poled samples can be found in a model of charge hopping and migration through defects. The diminished SH signal in the B-implanted sample is probably caused by the negative charge trapping layer, as well as by B${}_{2\alpha }$ and E${}^{\prime }$ center defects.

Reclusive single crystals of ammonium dihydrogen phosphate (ADP) and 0.1mol.% Acid Blue 22 dye-incorporated ADP were harvested by using a standard slow cooling mechanism. The skeletal framework of the anisotropic materials was analyzed by using single crystal X-ray diffraction cram. The powder X-ray diffraction examines the phase growth and incorporation of substituents in the crystalline matrices. The incorporation of additives in the system was examined by employing Fourier Transform Infrared Spectroscopy. The analysis of vibrational bands gives insights into the incorporation of additives in ADP crystal system. The transmission window of the specimen and optical bandgap of the given material were analyzed by using UV–Vis spectroscopic analysis. The incorporation of additives to parent crystals was examined by using Scanning Electron Microscope. The quantification of elements in the grown specimen was investigated by using Energy Dispersive X-ray spectroscopy. The mechanical rigidity of the material was inspected by using Vickers microhardness analysis. The piezoelectric charge coefficient of dye-incorporated ADP is higher than pristine ADP. The wettability of the material was identified by contact angle measurements. The optical stress was identified by employing photoelastic measurements. The second- and third-order nonlinear optical properties of pristine and dye-incorporated ADP crystals were investigated by using Kurtz–Perry powder technique and Z-scan technique.

In this paper, a theoretical investigation of electromagnetically induced transparency (EIT) using Laguerre–Gaussian (LG) beams has been carried out for the three canonical atom-laser coupled systems (e.g. $\mathrm{\Lambda }$-, V-, and $\mathrm{\Xi }$-type) in ${}^{87}$Rb atom. The required optical Bloch equations (OBEs) are derived for each system. The OBEs are analytically solved in steady-state condition under the weak probe field approximation. We have used the iterative perturbative technique to obtain the probe coherence term. The probe response w.r.t. probe detuning for different orders of the orbital angular momentum (OAM) number of both the pump and probe LG beams has been studied. We have also studied the effect of the OAM number on probe response in both Doppler-free and Doppler-broadened mediums. It has been observed that the EIT signal is squeezed for nonzero OAM number of the pump beam with arbitrary OAM number of the probe beam. It is found that for higher-order OAM number, the EIT signal is further squeezed. The modification of the EIT signal is attributed because of the spatial-dependent Rabi frequency. Our study demonstrates that the dynamic of the probe field inside an atomic medium may be controlled by tuning the OAM number of the LG beam.

We investigate the existence, stability and propagation dynamics of shock waves existing in defocusing saturable media modulated by a semi-infinite photonic lattice. Such surface waves consist of modulationally stable pedestals in bulk media and decaying oscillatory tails in semi-infinite photonic lattices. Due to Bragg-type reflection, they are strongly localized at the edge of the optical lattice. The kink steepness, pedestal height and localization degree can be controlled by propagation constant, saturable degree and lattice depth. Two types of kinks, i.e., “out-of-phase” and two branches of “in-phase” shock waves are revealed. Out-of-phase shock waves are stable in a substantial part of their existence domain. While the lower-branch in-phase waves with low energy flow are stable in almost their whole existence domain, the higher-branch in-phase waves are completely unstable. We thus show the first example of stable in-phase shock waves in nonlinear optics. Our findings provide new insight into the dynamics of semi-localized nonlinear surface shock waves or kink solitons.

This study reported nonlinear combination of multi-photon absorption and exciton–exciton collision induced random lasing (RL) emission from zinc oxide (ZnO) excited by femtosecond laser excitation. Strong RL with signal peaks centered at 407, 412 and 417nm while excited at 800nm wavelength pulses was observed. The threshold of the RL peak is about 0.9${\mathrm{\text{mJ/cm}}}^2$. Unlike the conventional three-photon excited RL phenomena centered at 390nm, the violet discrete lasing modes ranging from 407nm to 417nm may occur because of the excitonic stimulation. The red-shift of lasing mode signals may be attributed to exciton–exciton interaction enhanced electron–hole plasma emission.

We construct some new stochastic solutions for the fractional nonlinear Schrödinger type equation. Specifically, we introduce these stochastic solutions via geometric and beta distributions. Through these two statistical distributions, the expectation corresponding to solutions are illustrated to depict the influence of random parameters. Actually, the presented results can be used to explain many interesting phenomena in superfluid, optical fibers, plasma physics and vibration propagation in the ground and in structures. Some graphs are offered to illustrate the wave modes of the expectation corresponding to stochastic solutions. Finally, our analysis can be implemented for many other models in real life.