- 學位論文
吸附偶氮分子之蛋白石光子晶體之光調變光子能隙研究
Study of Optical Modulation of Photonic Band Gap of Opal Photonic Crystals Infiltrated with Disperse Red 1 Molecules
摘要
本論文當中，利用簡易的高溫吸附法將DR1分子吸附於蛋白石光子晶體之二氧化矽奈米球表面。首先將高溫下的樣品快速放入DR1分子溶液中，由於樣品的高溫，使得溶液中的溶劑，瞬間汽化，留下來的只剩DR1分子，因此達到高吸附DR1分子之二氧化矽蛋白石光子晶體。 另一方面，利用DR1分子具備光致發同分異構物特性，將激發雷射光照射吸附有DR1分子之二氧化矽蛋白石光子晶體，達到光調制光子能隙波長之特性。當激發光照射時，光子晶體之光子能隙反射峰會移至短波長，另外我們也發現反射峰位移量會隨激發光與探測光偏振方向安排而改變，進而探討不同偏振下，所產生的藍位移量之變化。另外當關掉激發光後，光子能隙反射峰值會在數秒內回復至原有波長，代表DR1分子之光致發同分異構特性可快速調制二氧化矽蛋白石光子晶體之光子能隙反射峰值。 另外也比較激發光在不同入射角照射吸附有DR1分子之二氧化矽蛋白石光子晶體所產生光子能隙反射峰位移性質，觀察激發光入射角何時可產生最大的位移量，何時又會獲得最小的位移量，藉此調查光子帶邊與光子能隙效應調變光子能隙反射峰值之能力。
並列摘要
A new method is introduced in this thesis to fabricate a silica (SiO2) opal photonic crystal (PhC) in which disperse-red-one (DR1) molecules are efficiently adsorbed on surfaces of SiO2 nanoparticles. First a SiO2 opal PhC was heated up to a high temperature and then was quickly soaked into a DR1 solution. The high temperature of the SiO2 opal PhC makes the solvent in the DR1 solution evaporate quickly so as to leave DR1 molecules been adsorbed on surfaces of SiO2 nanoparticles. Optically modulated photonic bandgap is demonstrated by irradiating laser light on a SiO2 opal PhC adsorbed with DR1 molecules thanks to photoisomerization of DR1 molecules. When the pumping laser light is turned on, the photonic bandgap reflection peak of the SiO2 opal PhC is blue-shifted whose magnitude depends on the polarization arrangement of the pump and probe beams. In addition, the photonic bandgap reflection peak of the SiO2 opal PhC can return its original position within few seconds after turning off the pump beam. These results indicate that the photoisomerization of DR1 molecules can be used to modulate the photonic bandgap reflection peak of the SiO2 opal PhC. Finally, we also investigate the influence of photonic bandedge and photonic bandgap effects on the shift of the photonic bandgap reflection peak of the SiO2 opal PhC by changing the incident angles of the pumping beam while the incident angle of the probe remaining the same. As the pumping beam is incident on the angles such that the pumping wavelength coincides with the photonic bandedge wavelength, the largest shift of reflection peak is obtained. On the other hand, when the pumping beam is incident on the angle so that the pumping wavelength coincides with the photonic bandgap wavelength, the smallest shift of reflection is observed.