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

理解光物质相互作用在现代成像系统中具有重要意义。这是越多的情况下，更大和更强的散射的对象是需要研究的。光通过弱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使用了相当长的一段时间，但最近也在现代光学显微镜。因此，同样在基于光片的显微镜中，空间光调制器用于调制照明光束的相位和强度，从而在原理上使得能够实现3D图像采集的许多优点。在这种情况下，贝塞尔光束的锥形相位轮廓揭示了一个惊人的能力，光束的自我重建和穿透深度增加了约50%，相对于传统的高斯光束。然而，在其狭窄的主强度峰周围，贝塞尔光束携带同心环系统，这导致在光片显微镜中的图像对比度的损失，如果没有特殊的技巧被应用。在这个建议中，我们希望使用线性和非线性光学方法，以改善照明光束的质量，在光片显微镜通过调查的依赖性的计算机全息产生的相位分布的光束传播特性。通过使用非线性光学的概念，我们的目标是提高单激光束的质量，从而提高照明光片的质量，使得贝塞尔光束环系统的影响被非线性地抑制。一方面，我们将使用双光子荧光激发的原理，特别是全息成形相位对短激光脉冲通过散射介质的传播的影响将被研究。另一方面，我们将应用STED原理，其中我们将使用高阶的第二自重构贝塞尔光束通过受激发射来耗尽环系统中的荧光。这里，我们希望最小化光片的厚度，从而通过提高耗尽效率来最大化光学分辨率。在第二步骤中，我们想要通过反馈全息控制来优化激发光束和STED光束的相位分布，使得在单个光束中产生的荧光将被显著改善，从而改善光片的质量。

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.