Static and dynamic properties of optical second harmonic generation in ferroelectric liquid crystal

Abstract

1991) Static and dynamic properties of optical second harmonic generation in ferroelectric liquid crystal, Ferroelectrics, 121:1, 259-274,

A new twist to molecular chirality: intrinsic chirality indices

“…This simple 'molecule' then appears to be optically active, and its optical activity is characterized by equation (ll). Expression (11) for the optical activity is just the kind of chirality measure we need, although it must be emphasized that we are using the model for optical activity only as a basis for non-local interactions.…”

“…Chiral molecules constrained to have some orientational order will form helical structures, such as chiral nematic or smectic phases, and the pitch of the helix can be related to the strength of the chiral interactions [9-]. In addition the broken symmetry of tilted smectic phases due to chirality permits the development of ferroelectric phases [ 10,] with a first-order nonlinear optical response [11]. For these chirality-based properties, the magnitude of the ferroelectric polarization [12,] of first-order nonlinear optical susceptibility depends on the chirality of the constituent molecules, which are often present as dopants.…”

Ferroelectric Liquid Crystals for Nonlinear Optics: Orientation of the Disperse Red 1 Chromophore along the Ferroelectric Liquid Crystal Polar Axis

“…The relatively low degree of polar order observed in this case is not surprising, since the p -nitroaniline derivative 2 was also shown to have very low extrapolated ferroelectric polarization, suggesting that the dimethylamino group does not provide a high degree of polar stereocontrol when situated ortho to the (1-methylalkyl)oxy chiral tail, while the nitro group provides polar excesses of greater than 30% in the “flipped” configuration. 4a,c In the present case the specific azo dyes 1 were chosen for ease of synthesis in these initial experiments to demonstrate the concept. Small polar excess notwithstanding, the results reported here clearly show that classic “large β” NLO chromophores can indeed be oriented along the polar axis in FLCs.…”

Liquid crystal displays, LC-materials and LPP photo-alignment

“…In 1991 Osaki and coworkers found that chiral smectic S C * ferroelectric liquid crystals (FLCs) are interesting candidates for realizing NLO-active organic materials [40]. FLCs are non-centro symmetric which is also prerequisite for NLO activity.…”

“…Moreover, to achieve large NLO-efficiency on the device level further requires interaction of light over sufficiently long distances; i.e., wave-guiding in a macroscopic molecular configuration is another prerequisite for success. Since not all of these partly contradictory requirements were taken into account by the FLC prior art, their NLO efficiency proved to be orders of magnitude below lithium niobate [40][41][42].…”