本論文研究在不同光源激發下，對偶氮染料摻雜液晶聚合物光子晶體的繞射強度所造成的影響。主要是透過調控激發在樣品的單道或兩道激發光的強度，使得樣品的繞射強度大小可以在一定範圍之內被切換，進而控制灰階繞射之效果。在實驗製程中利用全像術曝光的方式，以二道光(夾 38.9°)干涉，做四次曝光將干涉強弱分佈記錄在液晶-高分子材料中，形成有摻雜偶氮染料的全像液晶聚合物薄膜，透過 SEM 觀察結構分佈發現結構為三維的光子晶體。接著利用偶氮染料的光致同素異構效應(Photoisomerization)，以不同強度的綠光 (514 nm)和紫光 (405 nm)來激發，改變樣品中偶氮材料在cis態的濃度，使得液晶聚合物光子晶體中液晶球的雙折射性也跟著改變，進而調控出不同的繞射強度。
本實驗研究結果分成三個部分。其一，只以單道光激發時，繞射強度能變化的範圍較小，所以能夠切換的灰階數較少。其二，利用雙道光激發，同時以不同強度之紫光和綠光強度激發，可以比單道光激發切換更多個灰階，但是仍然有些繞射強度是無法被切換到的。其三，搭配單道光和雙光子激發，可以達到最佳化的灰階切換之效果。

This thesis investigates the influence of pumping beam on the diffraction from the photonic crystals based on azo dye-doped holographic polymer dispersed liquid crystals (HPDLCs). The diffraction is optically controllable through the tuning of intensity of single beam and/or two pumping beams. Experimentally, the azo dye-doped HPDLCs were fabricated holographically by using two-beam interference with four exposures. The structures were studied using scanning electron microscopy, and found to be a 3D photonic crystal. Due to photoisomerization of azo dye, different intensity of the pumping beam in the absorption spectrum of the sample can change the concentration of cis isomer,which in turn change the effective index of refraction of the droplets in HPDLC. Therefore, we can control the refractive modulation in azo dye-doped HPDLCs, and achieve gray-level diffraction switching in the process of pumping.
Three conclusions drawn from experimental results are as follows,
(1) The number of gray levels is few in the process of single pumping beam.
(2) Using two pumping beams simultaneously , we can improve the gray levels,
(3) The maximum of gray level switchings are achieved by combining single pumping beam and two pumping beams simultaneously.

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