Improving the Speed of Galvo-Scanners

摘要 光学方法提供高分辨率、非侵入性的神经功能测量， 从单个神经元到整个群体，在完整的大脑中。然而，有限的穿透深度， 空间尺度和时间分辨率仍然是光学成像的主要挑战。激光扫描 多光子显微术是用于散射脑中的细胞级成像的主要技术。 由于激光扫描显微镜的点扫描性质，光学扫描仪的速度 确定成像速度，即使在存在用于快速成像的足够信号强度时。为 惯性依赖扫描仪，如检流计和共振扫描仪，提高扫描速度 需要减小动态部件的惯性矩，而需要高空间 分辨率要求增加扫描镜的孔径。平衡这两种冲突 要求限制了商业上可用的电流计扫描仪在大约相同的 在过去的30到40年里，该提案的重点是展示一个新的概念， 提高基于振镜的光学扫描仪（振镜扫描仪）的扫描速度， 激光扫描显微镜的成像速度。所提出的新概念利用了单轴性质 电流计扫描，即，振镜扫描仪仅扫描一个空间维度，这使得 正交尺寸自由操作。通过使用圆柱形透镜将光束聚焦到扫描上 沿着检流计的轴向反射（即，非扫描方向）和另一个 柱面透镜对扫描后的光束进行准直，可以减小扫描镜的尺寸 显著地沿着非扫描方向。由此产生的镜子质量和力矩的减少 惯性将增加扫描速度，而不会减小扫描的视场和空间分辨率。 这项计划的提出与我们在开发脑成像技术方面的努力相一致。我们将 在激光扫描2光子和3光子显微镜中测试和验证新的扫描仪， 记录小鼠大脑活动。该计划的成功完成将创造新的光学 扫描仪，将提高所有基于振镜的激光扫描显微镜的成像速度。以来 设计，测试和演示都是基于典型的多光子显微镜，新概念可以 立即转移到其他研究实验室。此外，我们将与商业仪器合作， 建设者加速研究和采用该计划中开发的技术。

Abstract Optical methods provide high-resolution, non-invasive measurement of neural function, ranging from single neurons to entire populations, in the intact brain. Nevertheless, limited penetration depth, spatial scale and temporal resolution remain the main challenges for optical imaging. Laser scanning multiphoton microscopy is the main technology used for cellular-level imaging in scattering brains. Because of the point scanning nature of laser scanning microscopy, the speed of the optical scanner determines the imaging speed, even when there is sufficient signal strength for fast imaging. For inertially dependent scanners like galvanometers and resonant scanners, increasing the scan speed requires decreasing the moment of inertia of the dynamic component, while the need for high spatial resolution requires increasing the aperture of the scan mirror. The balancing of these two conflicting requirements has limited commercially available galvanometer scanners at approximately the same speed for the last 30 to 40 years. The focus of this proposal is to demonstrate a new concept that will improve the scan speed of galvanometer-based optical scanners (galvo-scanners), and increasing the imaging speed of laser scanning microscopy. The proposed new concept leverages the uniaxial nature of galvanometer scanning, i.e., a galvo-scanner scans one spatial dimension only, which leaves the orthogonal dimension free for manipulation. By using a cylindrical lens to focus the beam onto the scan mirror along the axial direction of the galvanometer (i.e., the non-scanning direction) and another cylindrical lens to recollimate the beam after scanning, we can reduce the size of the scan mirror dramatically along the non-scanning direction. The resulting reduction in mirror mass and moment of inertia will increase the scan speed without reducing the scanned field-of-view and spatial resolution. The proposed program dovetails with our effort in developing technologies for brain imaging. We will test and validate the new scanners in laser scanning 2-photon and 3-photon microscopes for in vivo recording of mouse brain activity. The successful completion of this program will create new optical scanners that will improve the imaging speed of all galvo-based laser scanning microscopes. Since the design, test and demonstration are all based on typical multiphoton microscopes, the new concept can be immediately translated to other research labs. Furthermore, we will work with commercial instrument builders to accelerate the research and adoption of the technology developed in this program.