Scalable, cost-effective, high-actuator-count deformable mirrors for astronomical adaptive optics

用于天文自适应光学的可扩展、经济高效、高执行器数量的可变形镜

• 批准号: 1105615
• 负责人: Thomas Bifano
• 金额: $ 89.92万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1105615&HistoricalAwards=false
• 关键词: Scalable; cost; effective; actuator; count

Over the past decade, adaptive optics (AO) has become indispensible as a means to compensate for aberrations introduced by atmospheric turbulence in large ground-based telescopes. The resulting gains in resolution are especially important for large telescopes. Indeed, because of their greater aperture, large ground-based telescopes have exceeded in narrow fields the fidelity possible with orbiting observatories and have led to exciting recent advances in the observation of exoplanets, characterization of planetary rings and atmospheres, and studies of galactic structure. The universal optical component that allows for this wavefront compensation is a deformable mirror (DM), which must operate at frequencies above 1 kHz and whose actuator count scales with the area of the telescope primary mirror. Indeed, DMs with tens of thousands of actuators are required for planned extremely large telescopes (ELTs) - those with apertures greater than ~20-m. The technology to make high-actuator density DMs with high production yield and therefore low cost does not exist today. A main objective of work planned by Dr. T. Bifano of Boston University is to develop such manufacturing technologies using a microelectromechanical systems (MEMS) approach. A critical failure mode of current large-format DMs has been the thousands of fragile electrical traces that route signals along the front surface from bonding pads located near the periphery of the module. This problem worsens rapidly as the actuator count increases, culminating in a yield of less than 1% for the latest attempts at constructing a high-count DM for the Gemini Planet Imager (GPI). Dr. Bifano's plans to circumvent this problem involve replacing the dense network of surface traces with through-wafer interconnects and bonding to a backside package. While this basic technique is not unprecedented in modern electronics manufacturing, technical challenges include the very large voltages (~250V) that must be endured by the silicon substrate to achieve the required DM stroke of ~3.5 microns. However, the payoff is large, since the availability of reliable high-actuator-count DMs would catalyze advances in promising imaging techniques such as Multi-Object AO and Extreme AO. An outcome of the proposed project will be fully functional MEMS DM prototypes with 2048 actuators, evaluated at a leading astronomical AO test bed. Funding for development high actuator count DMs for next-generation AO is being provided by NSF's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program.

在过去的十年中，自适应光学(AO)已经成为补偿大型地面望远镜中大气湍流引入的像差的一种不可或缺的手段。由此带来的分辨率提升对大型望远镜尤为重要。事实上，由于其较大的口径，大型地面望远镜在狭窄的视场中已经超过了轨道天文台可能达到的保真度，并导致在观测系外行星、描述行星环和大气层以及研究星系结构方面取得了令人兴奋的最新进展。实现这种波前补偿的通用光学部件是可变形反射镜(DM)，它必须在1 kHz以上的频率下工作，其致动器数量与望远镜主镜的面积成比例。事实上，对于计划中的超大型望远镜(ELT)-那些孔径大于~20米的望远镜-需要配备数万个致动器的DM。目前还不存在制造高致动器密度、高产量和低成本的DM的技术。波士顿大学的T.Bifano博士计划的工作的一个主要目标是利用微电子机械系统(MEMS)方法开发这种制造技术。目前的大尺寸DM的一个关键故障模式是数千条脆弱的电迹线，这些电迹线将信号从位于模块外围附近的焊盘沿前表面传送。随着执行器数量的增加，这个问题迅速恶化，最终导致为双子座行星成像仪(GPI)构建高计数DM的最新尝试的成品率不到1%。比法诺博士计划绕过这个问题，包括用贯穿晶片的互连取代密集的表面痕迹网络，并粘合到背面的封装上。虽然这种基本技术在现代电子制造中并非史无前例，但技术挑战包括硅衬底必须承受非常高的电压(~250V)，才能实现~3.5微米的DM冲程要求。然而，回报是巨大的，因为可靠的高致动器数量的DM的可用性将促进前景光明的成像技术的进步，如多对象AO和Extreme AO。拟议项目的成果将是具有2048个致动器的全功能MEMS DM原型，在领先的天文AO试验台上进行评估。NSF的天文科学部通过其先进技术和仪器计划为下一代AO的高致动器数DM的开发提供资金。