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 article, we describe an electrically switchable light beam steering component, based on the combination of microprism structures and nematic liquid crystals, which effectively deflects both a laser beam and a collimated white light beam with a controllable steering range of 38.
Wide bandgap GaN-based light emitting diodes (LEDs) have been intensively developed and revolutionized the solid-state lighting market in the past 10 years due to their ability to emit light ranging from ultraviolet to the short-wavelength part over the visible spectrum. However, there are some difficulties that limit the performance of GaN-based LEDs. The low light-extraction efficiency and straininduced quantum-confined Stark effect (QCSE) are the bottlenecks for high-power LEDs. For a GaN-based LED epi-structure, the lattice mismatch between InGaN and GaN results in strain and induces piezoelectric field. The field leads to the tilt of energy band structure and thus the separation of carriers in the active region, which decreases internal quantum efficiency (IQE) and causes wavelength shift of light emission. Great efforts are needed to overcome these obstacles in order to further improve the performance of LEDs.Low dimensional structures such as nanorods and nanowires have become prominent in recent years. With a diameter in nanoscale, the diode arrays may have advantages of increased surface to volume ratio due to sidewall etching and strain relaxation due to the vacant spaces among the rod array. Most researches on nanorod structure are restricted at material characterization. The process to
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