Feedback holographic control of self-reconstructing laser beams in strongly scattering media.

强散射介质中自重建激光束的反馈全息控制。

• 批准号: 239839440
• 负责人: Professor Dr. Alexander Rohrbach
• 金额: --
• 依托单位: Institut für Mikrosystemtechnik (IMTEK)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/239839440?language=en
• 关键词: Feedback; holographic; control; self; reconstructing

Light sheet based microscopy has had a strong impact on the development of novel intelligent illumination methods in modern microscopy, which improved 3D image quality significantly. This led to an advance in the areas of developmental biology and 3-D cell biology, but also made the investigation of laser beam propagation through strongly scattering media come to the fore. Recently it could be shown, that the phase profile of a weekly focused laser beam had a strong influence on light scattering in inhomogeneous, weekly absorbing media. In particular, Bessel beams revealed an amazing capability of beam self-reconstruction and a penetration depth which was increased by about 50% relative to conventional Gaussian beams. However, Bessel beams carry a concentric ring system, which results in a loss of image contrast in light sheet microscopy.In this proposal we want to use linear and nonlinear optical methods to improve the quantity of illumination beams in light sheet microscopy by investigating intensively the dependency of computer- holographically generated phase profiles on the beam propagation properties. In the area of linear optics, we aim to develop different read-out procedures for scattered light in different planes. Based on the extracted data, we then want to test and develop different wavefront correction procedures by feedback and iteration. The contrast diminishing influence of the ring system shall be reduced significantly by using a line-confocal detection system.In addition we aim to improve the quality of single laser beams and thereby of the illuminating light sheet by using nonlinear optical approaches, such that the influence of the Bessel beams ring system is nonlinearly suppressed. On the one hand we will use the principle of two-photon fluorescence excitation, where especially the influence of the holographically shaped phase on the propagation of short laser pulses through the scattering medium is to be investigated. On the other hand, we plan to apply the STED-principle, where we will use a second self-reconstructing Bessel beam of higher order to deplete the fluorescence in the ring system by stimulated emission. Here, we want to maximize the optical resolution by improving the depletion efficiency through time-gating in a first step. In a second step, we want to optimize the phase profiles of the excitation beam and the STED- beam by a feedback holographic control, such that fluorescence generated in the single beams will be improved significantly and thereby the quality of the light sheet.

基于光板的显微镜对现代显微镜中新型智能照明方法的发展产生了强烈的影响，从而显着提高了3D图像质量。这导致了发育生物学和3-D细胞生物学领域的进步，但也通过强烈散射介质对激光束传播进行了研究。最近，可以证明，每周聚焦激光束的相位曲线对不均匀，每周吸收培养基的光散射有很大的影响。尤其是，贝塞尔束揭示了束自我重建和穿透深度的惊人能力，相对于传统的高斯梁增加了约50％。然而，贝塞尔束带有同心环系统，在光片显微镜中导致图像对比度的损失。在此提案中，我们希望使用线性和非线性光学方法来改善光片显微镜中照明光束的数量，通过深入研究计算机上生成的相位谱图对光束传播属性的依赖性。在线性光学区域，我们旨在为不同平面中的散射光制定不同的读出程序。基于提取的数据，我们希望通过反馈和迭代来测试和制定不同的波前校正程序。通过使用线路相连检测系统，应显着降低环系统的对比度减小。在此外，我们旨在通过使用非线性光学方法来提高单个激光束的质量，从而提高照明光板的质量，以便非线性抑制Bessel Beams环系统的影响。一方面，我们将使用两光子荧光激发的原理，尤其是在该原理中，应研究全息相对短激光脉冲通过散射介质传播的影响。另一方面，我们计划应用Sted-principle，在这里我们将使用第二个自我重建的贝塞尔（Bessel）高阶贝塞尔（Bessel）束来通过刺激的发射来消耗环系统中的荧光。在这里，我们希望通过在第一步中通过时间门网提高耗竭效率来最大化光学分辨率。在第二步中，我们希望通过反馈全息控制来优化激发梁和steD梁的相位曲线，以便在单光束中产生的荧光将得到显着改善，从而大大改善光板的质量。