2009-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/705562摘要：Cr4+之超頻寬發光特性，吸引了全球很多研究群開發Cr&#25530;雜之光纖，目前以用雷射加熱生長法所提拉之Cr4+:YAG雙纖衣晶纖之螢光效率最佳，但Cr&#25530;雜之玻璃光纖，其製程上可利用光纖抽絲塔，因此，提拉速度快應用潛力極大，目前文獻上並不清楚在玻璃環境下之Cr4+發光截面積之影響機制，尤其在矽玻璃的矩陣內，有相當多四面體結構的可能性(註: Cr4+須在四面體結構才有近紅外螢光)，例如: SiO2, (SiO4)4-, (Si2O7)6-, (Si6O18)12-, (Si2O6)4-, (Si2O5)2-，但目前尚無相關文獻探討，在這些結構之螢光效率，是否其中某些可有與Cr4+:YAG相當之螢光截面，因此，我們希望藉近場掃描式光學顯微術來量測Cr4+:YAG雙纖衣晶纖之纖心、內纖衣及以光纖抽絲塔生長之Cr玻璃光纖螢光效率，以其奈米等級之空間解析度，嘗試是否能釐清這些不同四面體結構對Cr4+螢光截面之影響。 此外，目前全球其他研究群之光纖預型體，多為&#25530;雜Cr2O3之氧化鋁玻璃，再輔以一些二價做電荷補償之氧化物，而本計畫使用之光纖抽絲塔其預型體為由rod in tube之方法製成，即以Cr4+:YAG晶纖，插入熔融矽玻璃管，再以負壓做光纖抽絲，因此，纖心是由YAG與矽玻璃之擴散層構成，根據我們初步之TEM分析，纖心內含有許多20至50奈米直徑之Cr:-Al2O3晶體，這些奈米晶體之螢光特性尚待研究，本子計畫將嘗試以共焦顯微術量測微米尺度之纖心螢光特性，再配合以近場掃描式光學顯微術，量測個別奈米Cr:-Al2O3晶體之螢光特性，以找出最適當之纖心組成，提昇&#25530;Cr光纖之發光效率。 由於鉻離子屬過渡金屬，其未屏蔽之3d軌域電子，易受鄰近環境之影響，而改變螢光特性，我們將嘗試以tapered玻璃光纖探針或晶體光纖探針，為近場擾動源，並調變其與Cr:YAG樣品之距離，以探測Cr3+及Cr4+離子之螢光特性，從而分析Cr鄰近晶體場對<br> Abstract: The broadband nature of Cr4+ ion has attracted researchers worldwide to develop Cr doped fibers. Up to now, Cr4+:YAG crystal fiber grown by laser heated pedestal growth method has generated the highest fluorescence efficiency. Using drawing tower to fabricate Cr doped fibers has larger commercial potential because of its fast pulling speed. So far, it is not quite clear that the mechanisms that affect Cr4+ efficiency in glass environment. For example, the effects of the possible tetrahedral sites that may exist in silica fibers, such as SiO2, (SiO4)4-, (Si2O7)6-, (Si6O18)12-, (Si2O6)4-, and (Si2O5)2- clusters. In this proposal we plan to study it using a multi-wavelength confocal microscope and a near-field scanning optical microscope. In addition, the Cr doped fiber performs are usually using Cr2O3 and Al2O3 glass with some CaO for charge compensation. We have used a rod-in-tube technique to prepare our fiber perform, which results in plenty Cr:-Al2O3 nano crystals (20-50 nm in diameter) in the inner cladding. It is an inter-diffusion layer formed by YAG and silica glass. It would be interesting to know their fluorescence properties as well in order to find out better core and cladding compositions for higher efficiency. Since Cr ions belong to the transition metal group, the fluorescent spectra of its 3d electrons are apt to environmental matrix. We will try to use tapered glass fiber tip or crystal fiber tips to perturb its local electric field, and see their effects on the fluorescent properties. Theoretical model will be developed and simulated. In the first year, we will try to achieve 100-nm resolution in near-field fluorescence measurement of the fiber core and cladding to find out the effects of the nano crystals. Different thermal anneal treatments will be tried to raise fluorescent efficiency. In the second year, we will try to enhance the spatial resolution to 50 nm using our home-made sapphire crystal fiber tip. The saturation properties of the nano crystals will also be studied. In the third year, we will try to integrate the confocal and near-field techniques to realize an apertureless near-field scanning optical microscope with even higher spatial resolution. The local field of the Cr ions will be modulated to probe their temporal response.晶體光纖近場光學共焦顯微術光通信crystal fibernear field opticsconfocal microscopyoptical communication