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.

光学微观结构是材料表面在刻度上太小而无法用人眼观察到的材料表面的变形，但是可以有效地重定向光，从而使表面具有彩色甚至自缩的外观。这种结构自然发生，例如导致蝴蝶翼的鲜艳色彩。光学微观结构的合成结构在信息存储和显示等领域具有深远的技术影响，并且通常是基于将光敏膜暴露于灯或激光器的处方照明模式中。尽管该技术已经建立了良好的，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，制造的结构就不会在薄膜表面上。然而，已经发现一种新兴的有色有机分子和柔性聚合物的材料类别对照明方向而不是其亮度敏感。可以探索对光极化的敏感性，以制造动态的表面微观结构，不仅可以永久性光学微观结构，而且还可以响应光重新配置的结构。另外，最近可编程的空间光调节器的出现使得可以快速重新配置的极化光场的产生。拟议的研究将新的极化敏感聚合物与空间光调节器技术相结合，以创建用于静态和动态光学微结构的按需制造的台式系统。这样的系统将使多种光学制造商访问光裂面表面的快速原型，同时还可以使生物工程中的新技术依赖于使用微观表面研究细胞响应。该项目还将受益于TCNJ的教育和培训，这是一家小学的本科机构。该项目为本科科学专业的学生提供了出色的机会，可以获得综合经验。本科研究人员将成为一项多学科和国际研究计划的合作伙伴，该计划利用光子学和物质科学的新兴研究。光学微观结构是通过将光敏膜暴露于光学强度模式来制造的。尽管常规的光敏膜对光学强度做出反应并需要暴露后化学处理，但新的超分子静脉聚合物膜对光学极化做出反应，而表面微观结构立即响应照明，而无需随后处理。为了最好地利用这些新的极化敏感的材料，需要一个可编程的来源，该来源可以投影线性极化光的空间定义模式，例如空间光调节器。因此，拟议的研究将基于超分子叠氮化物材料和数字极化光学元件来开发新的微观结构制造系统。迈向这一发现的第一步是建立可使用空间光调节器获得的光学表面结构的放大器，分辨率和表面形貌。在多元素校正光学的基础架构之后，预计500 nm和2 µm的表面放大器的分辨率。第二个目标是利用多个暴露量的叠加具有适当确定的暴露时间和相位移位的叠加，从而利用空间光调节器的光电扫描能力为傅立叶合成。此外，还将探索启用空间照明调制器的数字光学系统的动态编程，以探索动态的表面微观结构。这种移动的表面结构只能在暴露于光学反应的氮杂聚合物等材料中诱导。通过对特征大小和结构的探索，将使用纳米印刷岩石造影研究拟南芥膜上光学表面微观结构的复制。原子力和扫描电子显微镜将完成这项工作，并将用于评估复制保真度。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响审查标准来评估被认为是宝贵的支持。

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.

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.

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