Nonlinear Optics of Nematic and Blue Phase Liquid Crystals

MAXWELL STRESS INDUCED FLOW-DEFORMATION AND OPTICAL NONLINEARITIES IN LIQUID CRYSTALS (Invited Paper)

“…These phase modulation effects have been observed before [43] using nanosecond laser pulses and an experimental set-up shown in Figure 9(a). In the case of a BPLC cell in which the laser induces a negative refractive index change [43], such phase modulation gives rise to a defocused beam with greatly attenuated on-axis power, cf. Figure 9(b).…”

“…However, it is clear from the analysis and results in the preceding section that such radially varying Stress would create a corresponding radially varying lattice distortion and refractive index modulation. Consequently the transmitted laser beam would acquire a transverse phase modulation that results in beam focusing/defocusing and other distortion effects [2,39,43,[45][46][47][48][49][50]. These phase modulation effects have been observed before [43] using nanosecond laser pulses and an experimental set-up shown in Figure 9(a).…”

“…Consequently the transmitted laser beam would acquire a transverse phase modulation that results in beam focusing/defocusing and other distortion effects [2,39,43,[45][46][47][48][49][50]. These phase modulation effects have been observed before [43] using nanosecond laser pulses and an experimental set-up shown in Figure 9(a). In the case of a BPLC cell in which the laser induces a negative refractive index change [43], such phase modulation gives rise to a defocused beam with greatly attenuated on-axis power, cf.…”

“…Recent studies have shown that another mesophase, namely, Blue-Phase Liquid Crystals (BPLC) present promising alternatives to NLC for electro-and nonlinear optics [32][33][34][35][36][37][38][39][40][41][42][43][44]. In this unique class of optical materials formed by mixing a chiral compound and nematics, the molecules self-assemble (without cell-surface alignment) into tightly wound defect-spirals that form 3-D body-centered cubic or simple cubic lattices with sub-wavelength lattice constants, cf.…”

“…Following the general discussion in previous sections, Maxwell Stress by the optical electric field of intense laser pulses will cause flows in transparent BPLC as well. Out studies [39,43] shown that in general, focused pulsed laser of intensity over several MW/cm 2 is required to generate observable effects. In the case of a Gaussian laser beam with a radial intensity distribution of the form…”