Measurements of Third Order Optical Nonlinearities of Nematic Liquid Crystals

Nonlinear optical properties of liquid crystals probed by Z-scan technique

“…In the case of 5CB, the nonlinear optical response is due mainly to the π-electrons of the benzene rings. Table 2 shows values of n 2 and β, obtained studying the nonlinear optical response in time scale of nanoseconds, of the 5CB, 8CB, E7 and CB15 thermotropic liquid crystals in the nematic phase [10]. For some of these TLC, e.g., 5CB, a strong nonlinear refraction and absorption have been observed but the mechanism that originate them are not yet well understood.…”

“…6. Lyotropic liquid crystals in the calamitic nematic (N c ) and isotropic phases were shown to present nonlinear refractive index n 2 ∼ −10 −6 esu [25,26], which is 10 2 smaller than that measured in 5CB in the same time scale [10]. At the N c phase, n 2 < 0 for both configurations between the nematic director and the electric field polarization of the beam.…”

“…Values of the nonlinear refraction index and nonlinear absorption, obtained in the picoseconds time scale in 5CB (4-cyano-4'-n-pentylbiphenyl) in the nematic phase, at different wavelengths by Palffy-Muhoray et al [10,11,12], are shown in Table 1.…”

Liquid crystals under high-power, nanosecond laser irradiation

“…Strong nonlinear absorption in the visible was observed in optical power limiting studies of LCs [41][42][43][44][45][46][47][48][49] and in z-scan measurements [50][51][52][53][54][55] . For the nematic phase, the two-photon absorption coefficient has a several-times-higher value for incident polarization parallel to the molecular dipole direction than for perpendicular polarization 37 .…”

Dispersion properties of liquid crystal core photonic crystal fibers calculated by a multipole method modified for anisotropic inclusions

“…When a LC core PCF is used for generating supercontinuum, it is expected that the spectrum of the generated supercontinuum can be controlled by changing temperature or an electric field since the dispersion properties of the PCF can be controlled by these effects. The nonlinear refractive index for homogeneously aligned 5CB (4-cyano-4′-n-pentylbiphenyl) LC at 24°C is measured to be 3.8 Â 10 À 18 m 2 /W using 33 ps optical pulses at 532 nm when an electric field is perpendicular to the director of LC [27]. This value is more than 100 times larger than that of fused silica.…”