IDBR: Agile Electronic Focus and Aberration Control for Live Animal Microscopy

蒙大拿州立大学的David Dickensheets博士获得了一笔赠款，用于开发一种具有灵敏电子对焦控制的光学显微镜。该项目解决了活体显微镜的主要技术障碍：通过厚的、未准备的标本成像时控制焦点和管理像差。我们将研究一种在电子控制下调整样品中焦点位置的方法，同时保持物镜在固定位置。该仪器将与基于ccd或扫描光束（共聚焦和双光子）类型的显微镜兼容，并且在高数值孔径下成像厚标本时，将为用户提供快速，全范围聚焦控制，而不需要试样台的z轴平移。在几种可能的光束聚焦控制技术中，MEMS可变形膜反射镜以其精度、速度和潜在的低成本而具有吸引力。然而，之前的实现受到运动范围的限制，因此在高NA下无法实现全范围对焦控制。该项目将开发新的MEMS膜镜，其位移比现有设备大一个数量级，并能够校正球差，从而在整个图像体积中保持高斯特雷氏比。改进是通过使用新的膜材料，精确的机械建模和一种新的闭环控制技术来实现稳定的静电驱动。该项目将开发新的反射镜和控制技术，并演示它们在两种不同的共聚焦显微镜应用的新仪器中的应用：发育中的鸡胚胎显微镜和人体皮肤显微镜。这项技术的潜在应用范围相当广泛。新仪器可以支持许多复杂的图像采集方案，包括倾斜切片，在高NA下增强聚焦深度，以及图像特征跟踪和稳定。该技术对未来用于腹腔镜、内窥镜或导管平台的小型化显微镜也至关重要，这些显微镜目前在原位调整焦点的能力非常有限。最后，该项目取得的进展将与广泛的静电MEMS致动器相关，并且可变形镜将在天文学，摄影，光学数据存储等方面的应用中引起兴趣。除了其科学影响外，该项目还包括研究和教育的整合，培养了两名工程博士研究生进行跨学科研究，并吸引了6名本科生参加工程设计团队。该项目还将参与蒙大拿学生和教师的暑期实习计划。美国部落学院。

A grant has been awarded to Dr. David Dickensheets at Montana State University to develop a light microscope with agile electronic focus control. This project addresses a major technological barrier for in vivo microscopy: controlling the focus and managing aberrations when imaging through thick, unprepared specimens. We will investigate a method that adjusts the location of the focus in the sample under electronic control while maintaining the objective lens in a fixed position. This instrument will be compatible with CCD-based or scanned beam (confocal and two photon) types of microscopes, and will give the user fast, full-range focus control when imaging thick specimens at high numerical aperture, without requiring z-translation of the specimen stage. Of the several possible technologies for beam focus control, MEMS deformable membrane mirrors are attractive for their precision, speed and potential low cost. However, previous implementations have suffered from limited range of motion, such that full range focus control at high NA was not possible. This project will develop new MEMS membrane mirrors capable of an order of magnitude more displacement than current devices and able to correct spherical aberration to maintain high Strehl ratio throughout the image volume. The improvement is achieved through the use of new membrane materials, accurate mechanical modeling and a new closed loop control technique for stable electrostatic actuation. This project will develop the new mirrors and control techniques, and demonstrate their use in a new instrument for two different confocal microscopy applications: microscopy of the developing chick embryo, and microscopy of human skin in vivo. The scope of potential use for this technology is quite broad. The new instrument could support many sophisticated image acquisition schemes including oblique sectioning, enhanced depth of focus at high NA, and image feature tracking and stabilization. The technology is also critical for future miniaturized microscopes designed for laparoscope, endoscope or catheter platforms that presently have extremely limited ability to adjust focus in situ. Finally, advances made in this project will be relevant for a broad class of electrostatic MEMS actuators and the deformable mirrors will be of interest for applications in astronomy, photography, optical data storage and others. In addition to its scientific impact the project embraces integration of research and education, training two engineering Ph.D. students in cross disciplinary research and engaging 6 undergraduate students in engineering design teams. This project will also participate in an established summer internship program for students and faculty from Montana?s tribal colleges.