BROADBAND FOCUSING FOR EXTREME MULTIMODAL MICROSCOPY

项目摘要 几乎所有用于生物成像的光学显微镜都基于折射物镜。 这些透镜的性能接近理论极限，然而，它们的使用受到限制 到可见光到近红外光谱范围。即使在这个范围内，它们的性能也只有 在相对较窄的范围内得到保证，宽带使用总是受到以下因素的影响： 色差另一个问题是群延迟色散，这些透镜 引入短光脉冲，这降低了非线性光学（NLO）信号的效率 显微镜下的一代这些缺点加在一起，严重损害了 几种NLO成像模式的成像特性， 荧光和三次谐波产生。此外，折射物镜根本无法 用于结合中红外（MIR）范围内的激发光的NLO技术，例如 如光热成像和和频产生，基于MIR的有前途的技术 分子对比度唯一可行的替代方案是全反射的施瓦兹希尔德-卡塞格伦 (SC)物镜，它本身是消色差的，但受到非理想点扩散函数的影响 以及限制吞吐量的中心遮蔽。由于这些限制，SC透镜具有 在生物成像应用中没有发现广泛的用途。这种表现的不足也是 令人兴奋的基于MIR-NLO成像技术的新进展的原因是， 窒息：根本没有高性能的高数值对焦选项， 支持这些新兴的成像技术。 在本计画中，我们开发一种新颖的全反射式高数值孔径透镜， 克服了SC聚焦透镜的所有限制。基于非同心设计，这款新 设计特点完美的色彩校正从紫外线到中红外线， 视场，显著降低群延迟色散，显著提高吞吐量 通过一起消除中心遮蔽。这种透镜不仅改进了现有的非线性光学 模式，依赖于宽带辐射，但也使新技术， 光热成像和SFG显微镜，迄今遭受低性能 聚焦光学系统

Project Summary Virtually all optical microscopes for biological imaging are based on refractive objective lenses. The performance of these lenses approaches the theoretical limit, however, their use is limited to the visible to near-infrared spectral range. Even within this range, their performance is only guaranteed over a relatively narrow range, and broadband use is invariably affected by chromatic aberrations. Another problem is the group delay dispersion that these lenses introduce to short optical pulses, which reduces the efficiency of nonlinear optical (NLO) signal generation in the microscope. Taken together, these shortcomings seriously compromise the imaging properties of several NLO imaging modalities such as three-photon excited fluorescence and third-harmonic generation. In addition, refractive objectives simply cannot be used for NLO techniques that incorporate excitation light in the mid-infrared (MIR) range, such as photothermal imaging and sum-frequency generation, promising technologies based on MIR molecular contrast. The only viable alternative is the all-reflective Schwarzschild-Cassegrain (SC) objective, which is inherently achromatic but suffers from a non-ideal pointspread function and a center obscuration that limits throughput. Because of these limitations, SC lenses have not found widespread use in biological imaging applications. This lack of performance is also the reason why advances in exciting new MIR-based NLO imaging technologies have been stifled: there simply are no high-performance high numerical focusing options available to support these emerging imaging technologies. In this project, we develop a novel all-reflective high numerical aperture lens that overcomes all limitations of the SC focusing lens. Based on a non-concentric design, this new design features perfect color correction from the ultra-violet to the mid-infrared, exhibits a wide field of view, dramatically reduces group delay dispersion and significantly improves throughput by eliminating the center obscuration all together. This lens not only advances existing NLO modalities that rely on broadband radiation, but also enables new technologies such as photothermal imaging and SFG microscopy that have thus far suffered from low performance focusing optics.