Nonradiative and Radiative Processes of Doped Nanocrystallites in Porous Glasses

0417807ALFANO该项目的目标是开始开发嵌入在多孔玻璃介质中的激光活性Cr4+掺杂纳米微晶，用于宽带激光和光放大应用(1100 nm到1600 nm)。这些材料结合了掺Cr4+晶体的良好辐射性能和玻璃的优点。拟议的研究将集中在克服这些问题并结合掺铬晶体的良好辐射性能和玻璃的优点的材料上。这种类型的介质可以被认为是单晶和玻璃之间的中间体。由于尺寸效应和纳米晶体与周围基质的良好隔离，掺杂纳米晶体的光学性质有望与块体材料的性质截然不同。掺杂纳米晶与玻璃基质之间的相互作用将为更好地理解固体中的非辐射猝灭机制提供信息。为了研究嵌入纳米晶体的多孔玻璃的光学性质和能量传递机制，将进行一系列光谱和时间分辨的拉曼测量。用SNOM和扫描共聚焦显微镜进行的空间分辨测量将揭示纳米晶体的局部光学性质。测量将对生长在玻璃基质气孔中的不同化学成分的掺杂纳米晶进行。样品将在纽约城市学院的内部准备。这项拟议的研究可能会导致设计出更高效的光子学材料，并有可能彻底改变用于光学放大器和激光器的宽带光通信和光学器件技术。该项目将整合研究和教育活动，以扩大促进技术进步和培训技术人员的机会。几名研究生和本科生将接受溶胶-凝胶材料制备、光谱测量和激光技术方面的培训，几名高中生(11-12年级)也将参与激光开发研究。

0417807ALFANOThe objective of this project is to initiate the development of laser Active Cr4+-doped nano-crystallites embedded in porous glass media for wide spectral band laser and optical amplification applications (1100 nm to 1600 nm). These materials combine favorable radiative properties of Cr4+-doped crystals and the advantages of glasses. The proposed research will be focus on materials that overcome these problems and combine favorable radiative properties of Cr4+ doped crystals and the advantages of glasses. Media of such type can be considered an intermediate between single crystals and glasses. The optical properties of doped nanocrystals are expected to be very different than the properties of bulk materials, due to size effects and good isolation of the nanocrystals from the surrounding matrix. The interaction between the doped nanocrystals and the glass matrix will provide information to better understand the nonradiative quenching mechanism in solids. To study the optical properties and energy transfer mechanisms in the porous glass with embedded nanosize crystals, a set of spectroscopic and time-resolved Raman measurements will be performed. Spatial resolved measurements with SNOM and Scanning Confocal microscopy will reveal optical properties locally at the nanocrystals. The measurements will be carried out on doped nanocrystals of different chemical compositions grown into pores of the glass matrix. Samples will be prepared in house at the City College of New York. The proposed research may lead to the design of more efficient Photonics materials and has the potential to revolutionize wide band optical communications and optical device technology for optical amplifiers and lasers. The project will integrate research and educational activities to Extend opportunity for advancing the technology and training of skilled personnel. Several graduate and undergraduate students will be trained in sol-gel material preparation, spectroscopic measurements and laser technology, several high school students (grades 11-12) will also become involved in laser development research.