Wang Kangni, Zheng Jihong, Lu Feiyue, Gao Hui, Palanisamy Aswin, Zhuang Songlin
Appl Opt. 2016 Jun 20;55(18):4952-7. doi: 10.1364/AO.55.004952.
A varied-line-spacing switchable holographic grating is demonstrated through a changeable interference pattern recorded in polymer-dispersed liquid crystal. The pattern is generated by the interference between one plane wave and another cylindrical wave. The line spacing and the period of grating can be controlled by varying the distance between the cylindrical lens and the grating sample and by changing the exposure angle between the two beams. Experimental period measurements and calculations show good agreement with the theoretical results. High diffraction efficiency of more than 80% for the middle period of the grating has been achieved under appropriate exposure time of 120 s and intensity of 19.1 mW/cm. In addition, the diffraction can be switched on and off by virtue of the external driving voltage of approximately 120 V. The grating also possesses a fast response with a rise time of 300 μs and a fall time of 750 μs. This grating, which can change the period in the grating structure to allow switchable diffraction of transmitted light, shows great potential application for diffractive optics.
通过记录在聚合物分散液晶中的可变干涉图案，展示了一种具有可变线间距的可切换全息光栅。该图案由一个平面波和另一个柱面波之间的干涉产生。通过改变柱面透镜与光栅样品之间的距离以及改变两束光之间的曝光角度，可以控制线间距和光栅周期。实验周期测量和计算结果与理论结果吻合良好。在120秒的适当曝光时间和19.1毫瓦/平方厘米的强度下，光栅中间周期的衍射效率达到了80%以上。此外，借助约120伏的外部驱动电压，可以打开和关闭衍射。该光栅还具有快速响应，上升时间为300微秒，下降时间为750微秒。这种能够改变光栅结构周期以实现透射光可切换衍射的光栅，在衍射光学领域显示出巨大的潜在应用价值。
