Two series of chiral salicylaldimine-based liquid crystals which differ from each other in the position of the (S)-2-octyloxy tail have been synthesized and characterized by polarizing optical microscopy, differential scanning calorimetry, and electrical switching. Compounds OH I (n = 6-7) having (S)-2-octyloxy tail close to the salicylaldimine core and compounds OH II (n = 6-11) having (S)-2-octyloxy tail far from the salicylaldimine core exhibit polymorphism of mesophases including frustrated blue phase and antiferroelectric (SmC*(A)) phases. Notably, as compared with structurally similar Schiff base compounds H I (n = 7), intramolecular hydrogen bonding in antiferroelectric salicylaldimine-based compounds OH I (n = 7) induces the frustrated blue phase. However, as compared with structurally similar Schiff base compounds OH II (n = 8), the lack of intramolecular hydrogen bonding in Schiff base compounds H II (n = 8) suppresses antiferroelectric properties.

We study the dynamics of a three-dimensional laser bullet propagating inside a nonlinear saturable medium. We show that an increase of the pump parameter destabilizes the bullet and leads to its destruction through oscillations with increasing amplitude. We propose an inhomogeneous and anisotropic external excitation mechanism leading to a stable oscillating bullet. By varying the frequency of the external excitation, a stable quasi-in-phase or quasi-antiphase internal state can be reached.

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