Study of Optical Modulation of Photonic Band Gap of Opal Photonic Crystals Infiltrated with Disperse Red 1 Molecules
| Autor: | Tsung Hsiang Chang, 張琮翔 |
|---|---|
| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 102 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. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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