Adaptive interferometric light-sheets for resolution enhanced imaging with and without labeling

了解光与物质的相互作用在现代成像系统中具有重要意义。这种情况越多，需要研究的物体散射越大，散射越强。光通过每周吸收物质的传播主要改变光的相位。因此，相位校正、自适应光学已经在天文学中应用了很长一段时间，最近也应用于现代光学显微镜。因此，在基于光片的显微镜中，空间光调制器也用于调制照明光束的相位和强度，从而在原则上为三维图像采集提供了许多优势。在这种情况下，具有锥形相位剖面的贝塞尔光束显示出惊人的光束自重建能力和穿透深度，相对于传统高斯光束增加了约50%。然而，在其狭窄的主强度峰周围，贝塞尔光束携带一个同心环系统，如果没有特殊的技巧，这将导致在薄片显微镜下图像对比度的损失。在这个建议中，我们想通过研究计算机全息生成的相位分布对光束传播特性的依赖关系，利用线性和非线性光学方法来提高光片显微镜中照明光束的质量。通过使用非线性光学概念，我们的目标是提高单束激光的质量，从而提高照明光片的质量，从而非线性地抑制贝塞尔光束环系统的影响。一方面，我们将利用双光子荧光激发原理，特别是全息形相位对短激光脉冲在散射介质中传播的影响进行研究。另一方面，我们将应用sted原理，其中我们将使用第二次高阶自重构贝塞尔光束通过受激发射耗尽环系统中的荧光。在这里，我们想要最小化光片的厚度，从而通过提高耗尽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光束和STED-光束的相位分布，从而显著提高单光束产生的荧光，从而提高光片的质量。

Understanding light matter interaction is of significant importance in modern imaging systems. This is the more the case, the larger and stronger scattering the object is that need to be investigated. Light propagation through weekly absorbing matter primarily changes the phase of light. Therefore phase correcting, adaptive optics has been used in astronomy for quite a while, but recently also in modern optical microscopy. Hence, also in light sheet based microscopy spatial light modulators are used to modulate the phase and the intensity of illumination beams, enabling in principle many advantages to 3-D image acquisition. In this context, Bessel beams with their conical phase profile reveal an amazing capability of beam self-reconstruction and a penetration depth which is increased by about 50% relative to conventional Gaussian beams. However, around their narrow main intensity peak, Bessel beams carry a concentric ring system, which results in a loss of image contrast in light sheet microscopy, if no special tricks are applied. In this proposal we want to use linear and nonlinear optical methods to improve the quality of illumination beams in light sheet microscopy by investigating the dependency of computer- holographically generated phase profiles on the beam propagation properties. By using nonlinear optical concepts, we aim to improve the quality of single laser beams and thereby of the illuminating light sheet, 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 will 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 minimize the thickness of the light sheet and thereby to maximize the optical resolution by improving the depletion efficiency. 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 the fluorescence generated in the single beams will be improved significantly and thereby the quality of the light sheet.