Читать книгу Liquid Crystals - Iam-Choon Khoo - Страница 29

Fabrications of fiber array by filling micro‐capillary array (see Figure 1.26) with optically isotropic liquid crystals (such as NLC in the liquid phase) are much easier, since there will not be any surface alignment and optical birefringent problems to deal with. Because of the fluid property and much lower scattering (practically negligible) loss in the isotropic phase, such fiber arrays of much longer propagation distance than conventional planar LC cells have been fabricated. These LC‐cored fiber arrays exhibit high‐quality image transmission and useful nonlinear optical properties for optical limiting action and sensor protection applications [50], as detailed in Chapter 12. Owing to their isotropic optical properties associated with their polycrystalline makeup, pristine BPLC [51] has also been employed as the guiding core to fabricate a similar nonlinear fiber array. Dye‐doped BPLC filled capillary (see Figure 1.27) has shown promising possibilities for random laser generation [52].

Figure 1.26. Schematic of a focused laser propagating through the guiding (liquid crystal) core of fiber inside a fiber array.

Figure 1.27. A capillary filled with dye‐doped BPLC core for random laser action.