液晶空间光调制器的调制特性测量

分析了液晶空间光调制器LC2002的工作原理,测量了振幅调制特性和最佳相位调制特性曲线.对经扭曲向列液晶空间光调制后的待测波面进行横向剪切干涉,用CCD记录其干涉图样,采用一维图像分析法得到最大相位调制为0.837π.实验证明液晶空间光调制器可以很好地进行相位调制.     

Enhancing light extraction of GaN-based blue light-emitting diodes by a tuned nanopillar arrayEnhancing light extraction of GaN-based blue light-emitting diodes by a tuned nanopillar array

Surface patterning of p-GaN to improve the light extraction efficiency of GaN-based blue light-emitting diodes （LEDs） has been investigated. Periodic nanopillar arrays on p-GaN have been fabricated by polystyrene （PS） nanosphere lithog- raphy; the diameter of the nanopillars can be tuned to optimize the electrical and optical properties of the LEDs. The electroluminescence intensity of the nanopillar-patterned LEDs is better than that of conventional LEDs; the greatest en- hancement increased the intensity by a factor of 1.41 at a 20 mA injection current. The enhancements can be explained by a model of bilayer film on a GaN substrate. This method may serve as a practical approach to improve the efficiency of light extraction from LEDs.     

Enhancing light extraction of GaN-based blue light-emitting diodes by a tuned nanopillar array

Surface patterning of p-GaN to improve the light extraction efficiency of GaN-based blue light-emitting diodes(LEDs) has been investigated. Periodic nanopillar arrays on p-GaN have been fabricated by polystyrene(PS) nanosphere lithography; the diameter of the nanopillars can be tuned to optimize the electrical and optical properties of the LEDs. The electroluminescence intensity of the nanopillar-patterned LEDs is better than that of conventional LEDs; the greatest enhancement increased the intensity by a factor of 1.41 at a 20 mA injection current. The enhancements can be explained by a model of bilayer film on a GaN substrate. This method may serve as a practical approach to improve the efficiency of light extraction from LEDs.