RUI: Spatial light modulator technology for the on-demand fabrication of optical microstructures in polarization-sensitive materials

RUI：用于在偏振敏感材料中按需制造光学微结构的空间光调制器技术

• 批准号: 2024118
• 负责人: David McGee
• 金额: $ 31.5万
• 依托单位: The College of New Jersey
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-15 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2024118&HistoricalAwards=false
• 关键词: RUI; Spatial; light; modulator; technology

Optical microstructures are deformations of a material surface on a scale too small to be seen with the human eye, but which can efficiently redirect light so as to give the surface a colored or even self-illuminated appearance. Such structures occur naturally, and for example lead to the brilliant colors of a butterfly wing. Synthetic fabrication of optical microstructures has had far-reaching technological impact in fields such as information storage and display, and is typically based on exposing a photosensitive film to a prescribed illumination pattern from a lamp or laser. While this technique is well-established, it is not suited for rapid prototyping. A separate limitation is that the fabricated structures are immobile on the film surface once the film processing is complete. However, an emerging material class of highly colored organic molecule coupled with a flexible polymer have been found to be sensitive to the direction of illumination and not its brightness. This sensitivity to light polarization can be exploited to make dynamic surface microstructures, enabling not only permanent optical microstructures, but also structures which can be reconfigured in response to light. Separately, the recent emergence of programmable spatial light modulators makes possible the generation of rapidly reconfigurable polarized light fields. The proposed research combines new polarization-sensitive polymers with spatial light modulator technology to create a benchtop system for the on-demand fabrication of both static and dynamic optical microstructures. Such a system will make rapid prototyping of light-diffracting surfaces accessible to a wide range of optical manufacturers, while also enabling new techniques in bioengineering that rely on the use of microscale surfaces to study cellular response. The project will also benefit education and training at TCNJ that is a primarily undergraduate institution. The project offers an outstanding opportunity for undergraduate science students to gain integrative experience. Undergraduate researchers will become partners in a multidisciplinary and international research program that leverages emerging research in photonics and material sciences. Optical microstructures are fabricated by exposing photosensitive film to an optical intensity pattern. While conventional photosensitive films respond to optical intensity and require post-exposure chemical processing, new supramolecular azopolymer films respond to optical polarization, with the surface microstructure growing immediately in response to illumination, with no subsequent processing required. To best leverage these new polarization-sensitive materials requires a programmable source that can project spatially-defined patterns of linearly polarized light, such as a spatial light modulator. The proposed research will therefore pursue the development of a new microstructural fabrication system based on supramolecular azopolymer materials and digital polarization optics. The first step towards this discovery is to establish the amplitude, resolution, and surface topographies of optical surface structures obtainable with the spatial light modulator. Resolutions of order 500 nm and surface amplitudes of 2 µm are expected following the incorporation of multielement corrected optics. A second goal is to exploit the optoelectronic scanning capability of the spatial light modulator to Fourier synthesize nonsinusoidal surface patterns using the superposition of multiple exposures with appropriately determined exposure times and phase shifts. In addition, the dynamic programmability of the spatial light modulator-enabled digital optics system will be exploited to explore dynamic surface microstructures. Such moving surface structures can only be induced in materials such as azopolymers which exhibit a reversible photomechanical response. Throughout this exploration of feature sizes and structures, the replication of optical surface microstructures on azopolymer films will be studied using nanoimprint lithography. Atomic force and scanning electron microscopy will complement this effort and will be used to assess replication fidelity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

光学微结构是材料表面的变形，其尺度太小以至于人眼无法看到，但它可以有效地重定向光，从而使表面具有彩色甚至自发光的外观。这种结构自然发生，例如导致蝴蝶翅膀的鲜艳颜色。光学微结构的合成制造在诸如信息存储和显示的领域中具有深远的技术影响，并且通常基于将光敏膜暴露于来自灯或激光的规定照明图案。 虽然这种技术是成熟的，但它不适合快速原型制作。 一个单独的限制是，一旦膜处理完成，制造的结构在膜表面上是固定的。 然而，已经发现与柔性聚合物耦合的高度着色的有机分子的新兴材料类别对照明的方向而不是其亮度敏感。 这种对光偏振的敏感性可以用来制造动态表面微结构，不仅可以实现永久的光学微结构，还可以实现响应于光而重新配置的结构。 另外，最近出现的可编程空间光调制器使得快速可重构偏振光场的产生成为可能。 拟议的研究将新型偏振敏感聚合物与空间光调制器技术相结合，以创建一个台式系统，用于按需制造静态和动态光学微结构。 这样的系统将使光衍射表面的快速原型制作能够被广泛的光学制造商使用，同时也使生物工程中依赖于使用微尺度表面来研究细胞反应的新技术成为可能。该项目还将有利于TCNJ的教育和培训，这是一个主要的本科院校。该项目为本科理科学生提供了一个获得综合经验的绝佳机会。本科研究人员将成为多学科和国际研究计划的合作伙伴，该计划利用光子学和材料科学的新兴研究。 光学微结构通过将光敏膜曝光于光强图案来制造。 虽然传统的光敏膜响应于光强度并需要曝光后化学处理，但新的超分子偶氮聚合物膜响应于光学偏振，其表面微结构响应于照射立即生长，而不需要后续处理。 为了最好地利用这些新的偏振敏感材料，需要一个可编程的源，可以投影空间定义的线性偏振光模式，如空间光调制器。 因此，拟议的研究将追求一个新的微结构制造系统的基础上超分子偶氮聚合物材料和数字偏振光学的发展。 这一发现的第一步是建立振幅，分辨率和表面形貌的光学表面结构可获得的空间光调制器。 采用多元校正光学元件后，预计分辨率可达500 nm量级，表面振幅可达2 µm。 第二个目标是利用空间光调制器的光电扫描能力，使用具有适当确定的曝光时间和相移的多次曝光的叠加来傅立叶合成非正弦表面图案。此外，将利用支持空间光调制器的数字光学系统的动态可编程性来探索动态表面微结构。 这种移动的表面结构只能在诸如偶氮聚合物的材料中诱导，这些材料表现出可逆的光机械响应。在整个探索的特征尺寸和结构，复制光学表面微结构的偶氮聚合物薄膜将研究使用纳米压印光刻。原子力和扫描电子显微镜将补充这一努力，并将用于评估复制fidelity.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

项目成果

Direct laser writing of micrograting arrays using a spatial light modulator

使用空间光调制器直接激光写入微光栅阵列

• DOI: 10.1117/12.2647393
• 发表时间: 2023
• 期刊: 1243304 (15 March 2023
• 作者: Strobelt, Jonas;Van Soelen, Matthew;McGee, David J.
• 通讯作者: McGee, David J.

Supramolecular Azopolymers for Dynamic Surface Microstructures Using Digital Polarization Optics

• DOI: 10.1002/adom.202202245
• 发表时间: 2023-03
• 期刊: Advanced Optical Materials
• 影响因子: 9
• 作者: Jonas Strobelt;Matthew Van Soelen;H. Abourahma;D. McGee

Optical microstructure fabrication using structured polarized illumination

使用结构化偏振照明制造光学微结构

• DOI: 10.1364/oe.451414
• 发表时间: 2022
• 期刊: Optics Express
• 影响因子: 3.8
• 作者: Strobelt, Jonas;Stolz, Daniel;Leven, Maximilian;Soelen, Matthew Van;Kurlandski, Luke;Abourahma, Heba;McGee, David J.
• 通讯作者: McGee, David J.