Adiabatic propagation in nematic liquid crystals with competing nonlinearities

Abstract

We theoretically investigate the influence of the variation of the nonlocal degree of the molecular orientation effect σ1 and the nonlocal degree of the thermal effect σ2 on beam propagation in nonlocal media with competing nonlinearities. According to the model proposed by JUNG P S, we find that variations in σ1 and σ2 have completely different effects on beam propagation in the medium. When σ1 increases, the beam tends to broaden, whereas when σ2 increases, the beam tends to compress. Numerical calculations, conducted using the split-step Fourier method, show that changes in σ2 have a smaller effect on propagation compared to σ1. Adiabatic propagation of the beam in nematic liquid crystals can be achieved if σ1 changes gradually, but not if σ1 changes abruptly. In contrast, adiabatic propagation can be realized with σ2 whether it changes abruptly or gradually. The variational results are well confirmed by numerical simulations.