Study of Laser-induced Adsorption and Ripple Structure in Dye-Doped Liquid Crystal Films

• Main Authors: Tian-Long Fu, 傅天龍
• Other Authors: Andy Ying-Guey Fuh
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/94607095781226542933

碩士 === 國立成功大學 === 物理學系碩博士班 === 91 === The main topic discussed in this thesis is the laser-induced effect in the dye-doped liquid crystal films. The phenomenon, in general, is caused by the dye molecule adsorption effect and the laser-induced ripple structure. These two effects are directly related to the polarization and the intensity of the laser (Ar+ laser at 514.5 nm), and the length of the exposure time. Under different conditions, the dye molecule adsorption and the groove (pattern) of the ripple structure distinctively. The lasers selected for this experiment are mainly 10 mW high intensity and 0.1mW low intensity lasers. The sample is prepared using a cell with one substrate treated homogeneous alignment. The other is not treated. Laser light enters (the sample) from the non-treared ITO glass substrate test side. The dye molecules adsorbed on the test side induce the twist structure in the liquid crystal along the easy axis and the homogeneous (rubbing) direction. Through the polarization microscope and a few simple experiment, we can deduce the adsorption effect and the ripple groove (pattern) at different laser intensity and time. The images obtained from SEM and AFM further confirm our experimental results.