Second-harmonic generation studies in the SmCP phase of bent-shaped mesogens

摘要

We have studied several compounds of non-chiral mesogens composed of symmetrically and non-symmetrically bent-shaped molecular core with thermally stable ester linkages and laterally substituted by methoxy group. Recently, mesomorphic properties have been described and the SmCP (B2) phase has been identified in a wide temperature range below the isotropic phase. Additionally, symmetrical bent-shaped mesogens exhibit the B7 phase on cooling from the B2 phase. Herein we concentrated on nonlinear optical properties in the observed mesophases. Second harmonic generation (SHG) supports the idea that the ground state of the B2 phase in studied bent-shaped mesogens has antiferroelectric character and demonstrates the switching from antiferroelectric to ferroelectric state under applied electric field.