In this paper, we present an electrically controllable microoptical component for light beam steering and light intensity distribution built on the combination of nematic liquid crystal (LC) and polymer microprisms. Polymer microprism arrays are fabricated using soft embossing with elastic polydimethylsiloxane molds and ultraviolet curable resins. Surface profiling measurements show that the dimensions of the replicated prisms closely approximate those of the master prism. Two different LC alignment techniques were employed: hybrid rubbing alignment and obliquely evaporated SiO 2 alignment, both of which result in proper alignment of the LC molecules along the prism groove direction. The operation voltage of the LC components is relatively low (10 V rms ). The steering angle of a green laser beam was experimentally studied as a function of applied voltage, and a steering range of 3 was found. The active LC components also effectively deflect a collimated white light beam over a steering angle of about 2 with an efficiency of 27%-33%. All the optical measurements are in agreement with theoretical calculations based on Snell's law.
In this paper, we propose a hybrid metallo-dielectric core-shell nanorod for the Kerker-type effect at two different frequencies. The effect arises from the interference of the scattering waves of the nanorod, which are generated by the magnetic dipole moment (MD) of the high-index hollow particle and the electric dipole moment (ED) induced in both metallic and dielectric particles. Interestingly, we find that such kind of unidirectional radiation properties, (i.e., zero back scattering occurring at dual frequencies) can be sustained with a single nanorod, which usually being equivalent to a local electric dipole source. The effect of substrate is also considered to investigate the typical experimental realization for the dual-frequency unidirectionalities of the nanoantenna. Furthermore, the unidirectionality can be further improved by the design of one-dimensional array of the hybrid nanoantenna. Our results could provide an additional degree of freedom for light scattering manipulation, and widen the versatile applications in nanoantennas, optical sensor, light emitters, as well as photovoltaic devices.
In the present work, the effect of alignment layers on blue phase liquid crystals was investigated. It was found that homogeneous alignment layers have profound selective influence on blue phase II (BPII). In the absence of alignment layers, BPII domains were randomly oriented and showed weak Bragg reflection in the UV, whereas with assistance of anchoring uniform domains with sharp Bragg reflection in the visible range appeared. On the other hand, the magnitude of Bragg shift in response to alignment layers in BPI is negligible. Domains of BP with alignment layers exhibit sharp Bragg reflection peaks (with FWHM < 15 nm), with very vivid colors and possessing fast switching speeds (<5 ×10−4 s). This simple method of selectively assisting one of the cubic phases is expected to be advantageous in the comparative studies of the two phases.
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