Korolkov Victor P, Nasyrov Ruslan K, Shimansky Ruslan V
Institute of Automation and Electrometry, Siberian Branch of the Russian Academy of Science, Prospekt Koptyuga 1, Novosibirsk 630090, Russia.
Appl Opt. 2006 Jan 1;45(1):53-62. doi: 10.1364/ao.45.000053.
Enhancing the diffraction efficiency of continuous-relief diffractive optical elements fabricated by direct laser writing is discussed. A new method of zone-boundary optimization is proposed to correct exposure data only in narrow areas along the boundaries of diffractive zones. The optimization decreases the loss of diffraction efficiency related to convolution of a desired phase profile with a writing-beam intensity distribution. A simplified stepped transition function that describes optimized exposure data near zone boundaries can be made universal for a wide range of zone periods. The approach permits a similar increase in the diffraction efficiency as an individual-pixel optimization but with fewer computation efforts. Computer simulations demonstrated that the zone-boundary optimization for a 6 microm period grating increases the efficiency by 7% and 14.5% for 0.6 microm and 1.65 microm writing-spot diameters, respectively. The diffraction efficiency of as much as 65%-90% for 4-10 microm zone periods was obtained experimentally with this method.
本文讨论了提高通过直接激光写入制造的连续浮雕衍射光学元件的衍射效率。提出了一种新的区域边界优化方法，仅在衍射区域边界的狭窄区域校正曝光数据。这种优化减少了与所需相位轮廓和写入光束强度分布卷积相关的衍射效率损失。一种描述区域边界附近优化曝光数据的简化阶梯过渡函数可适用于广泛的区域周期。该方法允许衍射效率有与单个像素优化类似的提高，但计算量更少。计算机模拟表明，对于周期为6微米的光栅，区域边界优化分别将0.6微米和1.65微米写入光斑直径的效率提高了7%和14.5%。使用该方法通过实验获得了4 - 10微米区域周期高达65% - 90%的衍射效率。
