混摻鑭系有機金屬化合物與非線性光學有機分子於以PQ 為光敏感劑之感光高分子材料在體積全像資訊儲存之特性研究

Abstract

本論文的研究方向，主要在改善以Phenanthrenequinone (PQ)為光敏感劑的感光高分子材料在全像資訊儲存的特性表現，期望能研發出具有更佳全像記錄的材料。在本論文中首先藉由添加五種鑭系有機金屬離子鑥（Lu3+）、鐿（Yb3+）、鉺（Er3+）、釹（Nd3+）、鈰（Ce3+）來改善9,10-phenanthrenequinone（PQ）/Poly(methyl methacrylate)的全像儲性質。並利用波長為532nm之雷射，量測繞射效率(Diffraction efficiency)與動態儲存範圍(M#)等不同的光學實驗，探討所製備之材料在全像記錄上的特性。在結果中發現摻入鑭系（Lanthanoid）有機金屬化合物後，全像記錄儲存特性其結果-繞射效率與動態儲存範圍M#表示為：Lu(ac)3 ＞ Yb(ac)3 ＞ Er(ac)3 ＞ PQ ＞ Nd(ac)3 ＞ Ce(ac)3。混摻Lu(ac)3感光高分子的繞射效率與動態儲存範圍M#與原感光高分子PQ/Poly（HEMA-co-MMA）相較之下都分別提升3.4倍與2倍。因此，全像體積特性增加的趨勢與原子序（atomic number）增加的次序是一致（Lu＞Yb＞Er＞Nd＞Ce）與金屬離子半徑次序是相反的（Lu3+ ＜Yb3+＜Er3+＜Nd3+ ＜Ce3+）。為了更加瞭解摻入鑭系有機金屬化合物之感光高分子的記錄機制，在FTIR和XPS等光譜的分析，發現了Lu（ac）3有機金屬化合物在曝光的過程中，Lu3+會與PQ分子上的氧產生鍵結Lu-O而使感光高分子曝光前後的折射率發生變化，使全像記錄的特性有顯著的提升。並利用UV-VIS的圖譜能階，嘗試了解樣品材料能隙（energy gap）與繞射效率的相關性。 另外，我們發現DMNA：PQ/PMMA感光高分子可以用紅光雷射647nm進行全像記錄其繞射效率最大值～43％，對2mm 厚的DMNA：PQ/PMMA感光高分子使用紅光雷射647nm記錄，其布拉格角度選擇率也非常接近理論預測的sinc 平方函數；全像光學圖案具有非常好的重建影像品質。這些實驗結果都說明了DMNA：PQ/PMMA感光高分子其材料敏感度延伸到原本單波長全像記錄不敏感的紅光波段，這個材料也可利於應用在較長波段的體積全像應用上。

This study describes an approach about improving the characteristics of photopolymer for holographic data storage. First of all, the diffraction efficiency (ηmax) and dynamic range (M#) of 9,10-phenanthrenequinone (PQ)–doped poly(methyl methacrylate) (PMMA) both improved significantly by co-doping five kinds of lanthanide organometallic ion lutetium (Lu3+), ytterbium (Yb3+), erbium (Er3+), neodymium (Nd3+) and cerium (Ce3+) into 9,10-phenanthrenequinone (PQ) / Poly ( hydroxyethyl methacrylate-co-methyl methacrylate) photopolymer. The diffraction efficiency and dynamic range (M #) was measured by 532nm the laser. The experimental results indicated that the performance for holographic data recording follows the order as: Lu(ac)3 > Yb(ac)3 > Er(ac)3 > PQ > Nd(ac)3 > Ce(ac)3. This order is corresponding to that of their atomic number (Lu > Yb > Er > Nd > Ce), but to the opposite order of the ionic radius(Lu+3 ＜ Yb+3＜ Er+3 ＜ Nd+3 ＜Ce+3) . Comparing that with the PQ singly doped P(HEMA-co-MMA) photopolymer samples, the maximal diffraction efficiency has been improved by 3.4 times to 98.3%, M/# had been improved by 2 times to 3.86, and the sensitivity was improved by 1.5 times. We also investigated the mechabism of Lu(ac)3-induced improvement in optical storage performance using FT-IR and X-ray photoelectron spectrocopyanalysis. In addition, we found that DMNA: PQ / PMMA photopolymer can be recorded by the 647nm red laser for holographic storage recording its maximum ~ 43% diffraction efficiency. A sinc-squared Bragg selection curve has been obtained and an image hologram reconstruction are also demonstrated. These experimental results support recording material for volume holographic applications in extended red spectral range.