Focused Ion Beam Fabrication of Optical Storage Structures Using Biphotonic Stimulation in Rare-Earth Doped Materials

这个向NSF提交的提案讨论了利用稀土掺杂半导体（如GaN）和绝缘体（特别是重金属氟化物玻璃如ZBLAN）的双光子上转换光发射的高密度档案光存储结构。我们计划利用聚焦离子束（FIB）技术作为将稀土（RE）物种的局部包密集地“写入”存储器的手段。我们将使用两种不同光子能量的激光器，通过对某些稀土离子（如Pr， Er, Tm）的两步双能量上转换过程，对数据进行选择性“读取”。我们已经获得了我们提出的方法的关键成分的初步结果：(1)制造用于RE植入的FIB源；(2)氮化镓中Pr的FIB注入和强光发射的证据；(3) ZBLAN微腔的FIB铣削；(4) ZBLAN双光子发射；(5)基于单片集成CMOS的光电探测器/接收器阵列的制造和表征，该阵列提供可调谐的光功率阈值，并且对低功率光信号高度敏感。此外，我们还构建了一个光存储介质表征系统，使我们能够评估用于光存储应用的稀土掺杂样品的可行性。除了允许在各种光激发方案下对稀土掺杂样品进行目测外，我们开发的表征系统还提供了在单/多个数据位上执行光学表征（光谱和光功率测量）的能力。最后，该表征系统将CMOS光电接收器阵列集成到一个伪读头组件中，该组件允许对掺杂re的光存储介质进行面向位、面向字或面向页的读取。我们的初步结果表明我们所开发的整体光存储器概念是可行的。在这里提出的工作中，我们计划研究FIB写入过程中获得最大比特存储密度的限制，以及在双光子读取操作中获得最高信噪比的方法。为了评估存储器性能参数（如数据速率、访问时间、误码率、位串扰和页串扰），我们计划设计、制造和表征包含103位阵列的存储介质和检测结构。

ECS-9906984StecklThis proposal to NSF discusses a high density archival optical memory structure using biphotonic upconversion photoemission from rare-earth-doped semiconductors (such as GaN) and insulators (especially heavy metal fluoride glasses such as ZBLAN). We plan to utilize focused ion beam (FIB) techniques as the means for densely "writing" the memory with localized packets of rare earth (RE) species. We will use two lasers of different photon energy to perform selective "reading" of the data through the two-step, two-energy upconversion process in certain rare earth ions (such as Pr, Er, Tm). We have obtained preliminary results on the critical ingredients of our proposed approach: (1) fabrication of FIB sources for RE implantation; (2) FIB implantation of Pr into GaN and evidence of strong photoemission; (3) FIB milling of microcavities in ZBLAN; (4) biphotonic emission from ZBLAN; (5) fabrication and characterization of a monolithically integrated CMOS based photodetector/receiver array that provides a tunable optical power threshold and is highly sensitive to low power optical signals. Further, we have constructed an optical storage media characterization system that allows us to evaluate the viability of RE-doped samples generated for optical storage applications. In addition to allowing visual inspection of RE doped samples under various optical excitation schemes, the characterization system we have developed provides the capability to perform optical characterization (spectroscopic and optical power measurements) on single/multiple data bits. Finally, the characterization system incorporates the CMOS photoreceiver array into a pseudo read-head assembly that allows for bit-oriented, word-oriented or page-oriented reading of an RE-doped optical storage media.Our preliminary results indicate the feasibility of the overall optical memory concept which we have developed. In the work proposed here, we plan to investigate the limits of the FIB write process for obtaining maximum bit storage density and approaches for obtaining the highest signal-to noise ratio in the biphotonic read operation. To evaluate the memory performance parameters (such as data rate, access time, bit error rate, bit-cross-talk and page-cross-talk), we plan to design, fabricate and characterize storage media and detection structures containing arrays of 103 bits.