Wavefront-Engineering Microscopy Group, Photonics Department, Institut de la Vision, Sorbonne University, Inserm S968, CNRS UMR7210, Fondation Voir et Entendre, Paris, France.
Nat Methods. 2020 Jun;17(6):571-581. doi: 10.1038/s41592-020-0795-y. Epub 2020 Apr 13.
Temporal focusing, with its ability to focus light in time, enables scanless illumination of large surface areas at the sample with micrometer axial confinement and robust propagation through scattering tissue. In conventional two-photon microscopy, widely used for the investigation of intact tissue in live animals, images are formed by point scanning of a spatially focused pulsed laser beam, resulting in limited temporal resolution of the excitation. Replacing point scanning with temporally focused widefield illumination removes this limitation and represents an important milestone in two-photon microscopy. Temporal focusing uses a diffusive or dispersive optical element placed in a plane conjugate to the objective focal plane to generate position-dependent temporal pulse broadening that enables axially confined multiphoton absorption, without the need for tight spatial focusing. Many techniques have benefitted from temporal focusing, including scanless imaging, super-resolution imaging, photolithography, uncaging of caged neurotransmitters and control of neuronal activity via optogenetics.
时间聚焦，通过在时间上聚焦光的能力，实现了在样品上用微米级轴向限制对大表面积进行无扫描照明，并能在散射组织中稳健传播。在传统的双光子显微镜中，广泛用于活体动物中完整组织的研究，通过对空间聚焦的脉冲激光束进行点扫描来形成图像，导致激发的时间分辨率有限。用时间聚焦的广角照明代替点扫描消除了这一限制，这是双光子显微镜的一个重要里程碑。时间聚焦使用放置在与物镜焦平面共轭的平面中的扩散或色散光学元件来产生与位置相关的时间脉冲展宽，从而实现轴向限制的多光子吸收，而无需严格的空间聚焦。许多技术都受益于时间聚焦，包括无扫描成像、超分辨率成像、光光刻、笼状神经递质的释放以及通过光遗传学控制神经元活动。
