Microscale Adaptive Optical Wavefront Correction

微尺度自适应光学波前校正

• 批准号: 0010026
• 负责人: Gert Cauwenberghs
• 金额: $ 30万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2005-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0010026&HistoricalAwards=false
• 关键词: Microscale; Adaptive; Optical; Wavefront; Correction

Phase distortions due to inhomogeneities in the optical path severely limit the perforinancc of a large class of optical systems for ground-to-ground and space communications, imaging through the atmosphere, medical laser beam focusing, among others. Demands on increased spatial resolutions and larger bandwidths call for an integrated approach to adaptive optics that modulates the wavefront in parallel at microscopic scale.This collaborative effort combines expertise in adaptive optics, analog parallel very-large scale integrated (VLSI) niicrosys-tems, microfabrication and liquid-crystal molecular systems to create a new generation of adaptive micro-optical systems for high-resolution wavefront correction, with over 10,000 fully autonomous control elements integrated on a single, hybrid opti-cal/electronic chip. Autonomy is essential for high-bandwidth operation, and is obtained by integrating all adaptive functions directly on-chip.At the architectural level, model-free adaptive control is implemented using parallel perturbation stochastic gradient descent optimization of an arbitrary, externally provided metric of system performance. At the physical level, high-speed wavefront control at micro-scale resolution is obtained by integrating a new type of fast nematic liquid-crystal (LC), operating at kilohertz- range bandwidths, onto the adaptive control chip. Silicon-on-sapphire (SoS) technology with ultra-thin silicon (UTSi) transis-tors provides a high-quality, low-noise, transparent active medium for high-density optical and electronic integration. We will investigate microscale structures of LC material sandwiched in between two transparent SoS wafers, implementing arrays of phase modulators with active electrodes implementing the adaptive algorithms in parallel. directly interfacing with the wave- front. The architectural and technological innovations combine to yield a projected system performance in excess of 108 control updates/sec. at least a factor 1,000 better than presently existing adaptive optics systems in speed, density and cost.This program integrates research and education in a sequence of project-intensive courses, where teams of graduate and undergraduate students learn to design. prototype and test adaptive optics co-processors, implemented in analog VLSI and fabricated through MOSIS. The adaptive co-processors will be configured to externally control a variety of fast LC and other spatial light phase modulators, available for experimentation at the Army Research Laboratory (ARL). In addition, we will make use of full-size UTSi SoS wafers provided by Peregrine Semiconductor, custom-fabricated in a special arrangement with Hopkins, to prototype a fully integrated version of consistent optical quality. The already polished SoS wafers will be post-processed at the JHU Microfabrication Laboratory and at Boulder Nonlinear Systems. Inc.. to pattern and deposit fast nematic LC in contact with SoS for fast spatial light phase modulation. The prototyped adaptive micro-optical systems will be experimentally demonstrated on various adaptive optics and imaging tasks including laser beam focusing and stabilization for optical communications.

由于光路不均匀性导致的相位畸变严重限制了地对地和空间通信、大气成像、医用激光束聚焦等一大类光学系统的性能。对提高空间分辨率和更大带宽的需求需要一种自适应光学集成方法，在微观尺度上并行调制波前。这种协作努力结合了自适应光学、模拟并行超大规模集成 (VLSI) 微系统、微加工方面的专业知识。和液晶分子系统，创建新一代自适应微光学系统，用于高分辨率波前校正，将超过 10,000 个完全自主的控制元件集成在单个混合系统上光学/电子芯片。自主性对于高带宽操作至关重要，并且是通过直接在片上集成所有自适应功能来获得的。在架构级别，使用任意外部提供的系统度量的并行扰动随机梯度下降优化来实现无模型自适应控制表现。在物理层面，通过将工作频率为千赫兹范围的新型快速向列液晶（LC）集成到自适应控制芯片上，可以实现微尺度分辨率的高速波前控制。具有超薄硅 (UTSi) 晶体管的蓝宝石上硅 (SoS) 技术为高密度光学和电子集成提供了高质量、低噪声、透明的有源介质。我们将研究夹在两个透明 SoS 晶圆之间的 LC 材料的微型结构，实现带有有源电极的相位调制器阵列，并行执行自适应算法。直接与波前连接。架构和技术创新相结合，预计系统性能将超过每秒 108 次控制更新。在速度、密度和成本方面比目前现有的自适应光学系统至少高出 1,000 倍。该计划将研究和教育整合到一系列项目密集型课程中，研究生和本科生团队在其中学习设计。原型并测试自适应光学协处理器，在模拟 VLSI 中实现并通过 MOSIS 制造。自适应协处理器将配置为从外部控制各种快速LC和其他空间光相位调制器，可用于陆军研究实验室（ARL）的实验。此外，我们将利用 Peregrine Semiconductor 提供的全尺寸 UTSi SoS 晶圆（与 Hopkins 进行特殊安排定制制造）来制作具有一致光学质量的完全集成版本的原型。已经抛光的 SoS 晶圆将在 JHU 微加工实验室和博尔德非线性系统公司进行后处理。 Inc. 图案化并沉积与 SoS 接触的快速向列液晶，以实现快速空间光相位调制。原型自适应微光学系统将在各种自适应光学和成像任务中进行实验演示，包括激光束聚焦和光通信稳定。