Zonal Bimorph Deformable Mirror Feasibility Study

分区双压电晶片变形镜可行性研究

• 批准号: PP/E003249/1
• 负责人: Andrew Doel
• 金额: $ 2.5万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=PP%2FE003249%2F1
• 关键词: Zonal; Bimorph; Deformable; Mirror; Feasibility

The atmosphere is in a constant state of flux. Different pockets of air have different temperatures and densities which affect the light passing through it in different ways. This 'turbulence' limits how well you can see distant objects, and effectively puts a limit on the resolution that can be achieved with ground based telescopes. However, at the size of ground-based telescopes has gradually been increasing due to the advent of adaptive optics; this can be used to correct for the blurring caused by turbulence. There are now a number of Very Large Telescopes (VLTs), with 8-10 meter diameters that have been commissioned with adaptive optics. Based on the success of these systems, a much larger facility, the Extremely Large Telescope, (ELT), with a diameter of 30 meters is now being considered by a European Consortium lead by the European Southern Observatory (ESO) The Zonal Bimorph Deformable Mirror (ZBDM) is an important new AO technology that has resulted from five years of investment at BAE SYSTEMS Advanced Technology Centre. ZBDMs exploit the benefits normally associated with bimorph mirrors; simple construction, cost effective manufacture, and inherent ruggedness, but at the same time, they have the potential to be scaled up to large apertures with many thousands of elements. In addition, the low element capacitance (typically two orders of magnitude less than that of an equivalent stacked actuator DM), will make the driver for the mirror significantly easier to implement with much less heat dissipation. The main objective of this proposal is to carry out a risk reduction study on the development of this technology for medium (2-5mm pitch, 200-400mm aperture) sized deformable mirrors for the Astronomical Instrumentation which is to be included in the planned European Extremely Large Telescope facility (e.g. for multi-conjugate adaptive optics and for the planet-finder instrument). ZBDM technology has the flexibility to fulfil a number of AO roles. One particular area is to offer a solution to the limitations in the maximum stroke available with high density (2-5mm) DM's. For example, 2mm pitch mirrors based on stacked actuator technology typically provide a maximum stroke of 2um. The thin, lightweight ZBDM structure should enable the integration of both 'tweeter' and 'woofer' DMs to realise a dual-stage, high PV stroke 'planet-finder' class device. A single layer, 61 element test mirror fabricated using internal funds has recently demonstrated an inter-actuator stroke of +/-1.4um, coupled with a lowest device resonance of 5 kHz and a PV stroke of +/-8um. Analytical modeling suggests that a dual stage ZBDM with a tweeter pitch of 2mm could deliver a maximum stroke of +/-5um. This proposal covers a two year risk reduction programme that would be exploited through a bid into the FP7 programme to progress the technology towards a full scale prototype. The main objective of this first stage is to undertake a series of risk reduction exercises which will increase the maturity of the technology, and to fabricate a small scale demonstrator which will provide a firm basis for the full scale prototype phase. o Device models will be used to determine the characteristic trade-off between maximum peak-valley (PV) stroke and bandwidth, the range of influence functions that can be achieved, and the inter-dependence of layers for a dual stage mirror. o Assembly and polishing trials will be undertaken in order to determine the best way to reduce / eliminate the risk of print through and maximize mirror flatness. o The current design is based on standard 'soft' PZT, which exhibits hysteresis; a number of strategies for reducing this effect have already been identified. These will be assessed, and the most promising technique will be used in the small scale demonstrator. While ZBDM technology can also be applied to larger mirror types, these applications are being addressed directly by the ELT Large AO Mirror Programme.

大气处于不断变化的状态。不同的空气袋具有不同的温度和密度，这会以不同的方式影响通过它的光。这种“湍流”限制了你能看到远处物体的程度，并有效地限制了地面望远镜所能达到的分辨率。然而，由于自适应光学的出现，地面望远镜的尺寸逐渐增加;这可以用来校正湍流造成的模糊。现在有许多直径为8-10米的甚大望远镜（VLT）已经使用自适应光学进行了调试。基于这些系统的成功，一个更大的设施，直径为30米的极大望远镜（ELT），现在正在考虑由欧洲南方天文台（ESO）领导的欧洲联盟。ZBDM利用了通常与双压电晶片反射镜相关的优点;简单的构造、成本有效的制造和固有的坚固性，但同时，它们具有放大到具有数千个元件的大孔径的潜力。此外，低元件电容（通常比等效堆叠致动器DM的电容小两个数量级）将使得用于反射镜的驱动器明显更容易以少得多的热耗散来实现。这项建议的主要目的是就为拟列入计划中的欧洲超大望远镜设施的天文仪器（例如，用于多共轭自适应光学和行星探测仪）开发中型（间距2- 5毫米，孔径200- 400毫米）可变形反射镜的技术进行减少风险研究。ZBDM技术具有实现许多AO角色的灵活性。一个特殊的领域是提供解决方案，以限制最大行程可与高密度（2- 5毫米）DM的。例如，基于堆叠致动器技术的2 mm间距反射镜通常提供2um的最大行程。ZBDM结构轻薄，可集成高音和低音DM，实现双级、高PV冲程的行星探测器级器件。使用内部资金制造的单层61元件测试镜最近证明了+/-1.4 μ m的致动器间冲程，以及5 kHz的最低器件谐振和+/-8 μ m的PV冲程。分析模型表明，具有2 mm高音单元间距的双级ZBDM可以提供+/-5um的最大冲程。该提案涵盖了一项为期两年的风险降低计划，该计划将通过竞标FP 7计划来利用，以将该技术推向全尺寸原型。第一阶段的主要目标是进行一系列降低风险的演习，以提高技术的成熟度，并制造一个小规模的演示器，为全尺寸原型阶段提供坚实的基础。o器件模型将用于确定最大峰谷（PV）行程和带宽之间的特性权衡、可以实现的影响函数的范围以及双级反射镜的层的相互依赖性。o将进行组装和抛光试验，以确定减少/消除印透风险并最大限度地提高镜面平整度的最佳方法。目前的设计是基于标准的“软”PZT，它表现出滞后;已经确定了一些减少这种影响的策略。这些将被评估，最有前途的技术将用于小规模的演示。虽然ZBDM技术也可以应用于更大的反射镜类型，但ELT大型AO反射镜计划直接解决了这些应用。

项目成果

Progress on the development of a zonal bimorph deformable mirror

带状双压电晶片变形镜研制进展

• DOI: 10.1117/12.787892
• 发表时间: 2008
• 作者: Griffith M

Integrated dual-stage deformable mirrors

集成双级变形镜

• DOI: 10.1117/12.856965
• 发表时间: 2010
• 作者: Griffith M