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Multiple light scattering hampers imaging objects in complex scattering media. Approaches used in real practices mainly aim to filter out multiple scattering obscuring the ballistic waves that travel straight through the scattering medium. Here, we propose a method that makes the deterministic use of multiple scattering for microscopic imaging of an object embedded deep within scattering media. The proposed method finds a stack of multiple complex phase plates that generate similar light trajectories as the original scattering medium. By implementing the inverse scattering using the identified phase plates, our method rectifies multiple scattering and amplifies ballistic waves by almost 600 times. This leads to a significant increase in imaging depth—more than three times the scattering mean free path—as well as the correction of image distortions. Our study marks an important milestone in solving the long-standing high-order inverse scattering problems. Deep imaging in complex scattering media is hindered by multiple light scattering. Here, the authors proposed a method to trace multiple scattering trajectories in situ using a recorded reflection matrix and achieved enhanced imaging depth by converting these multiple scattering to signal waves. [ABSTRACT FROM AUTHOR]

Myelination processes are closely related to higher brain functions such as learning and memory. While their longitudinal observation has been crucial to understanding myelin-related physiology and various brain disorders, skull opening or thinning has been required to secure clear optical access. Here we present a high-speed reflection matrix microscope using a light source with a wavelength of 1.3 μm to reduce tissue scattering and aberration. Furthermore, we develop a computational conjugate adaptive optics algorithm designed for the recorded reflection matrix to optimally compensate for the skull aberrations. These developments allow us to realize label-free longitudinal imaging of cortical myelin through an intact mouse skull. The myelination processes of the same mice were observed from 3 to 10 postnatal weeks to the depth of cortical layer 4 with a spatial resolution of 0.79 μm. Our system will expedite the investigations on the role of myelination in learning, memory, and brain disorders.The authors realize longitudinal deep-brain imaging through an intact mouse skull by constructing a high-speed reflection matrix microscope at 1.3 µm wavelength and developing a computational conjugate adaptive optics algorithm eliminating skull aberrations. [ABSTRACT FROM AUTHOR]

The efficient delivery of light energy is a prerequisite for the non-invasive imaging and stimulating of target objects embedded deep within a scattering medium. However, the injected waves experience random diffusion by multiple light scattering, and only a small fraction reaches the target object. Here, we present a method to counteract wave diffusion and to focus multiple-scattered waves at the deeply embedded target. To realize this, we experimentally inject light into the reflection eigenchannels of a specific flight time to preferably enhance the intensity of those multiple-scattered waves that have interacted with the target object. For targets that are too deep to be visible by optical imaging, we demonstrate a more than tenfold enhancement in light energy delivery in comparison with ordinary wave diffusion cases. This work will lay a foundation to enhance the working depth of imaging, sensing and light stimulation. The use of a time-gated reflection matrix of a scattering medium, in particular via using singular value decomposition and injecting light into the largest time-gated eigenchannel, can lead to a more than tenfold enhancement in light energy delivery in comparison with ordinary wave diffusion cases. [ABSTRACT FROM AUTHOR]

Optical microscopy suffers from a loss of resolving power when imaging targets are embedded in thick scattering media because of the dominance of strong multiple-scattered waves over waves scattered only a single time by the targets. Here, we present an approach that maintains full optical resolution when imaging deep within scattering media. We use both time-gated detection and spatial input-output correlation to identify those reflected waves that conserve in-plane momentum, which is a property of single-scattered waves. By implementing a superradiance-like collective accumulation of the single-scattered waves, we enhance the ratio of the single scattering signal to the multiple scattering background by more than three orders of magnitude. An imaging depth of 11.5 times the scattering mean free path is achieved with a near-diffraction-limited resolution of 1.5 μm. Our method of distinguishing single- from multiple-scattered waves will open new routes to deep-tissue imaging and studying the physics of the interaction of light with complex media. [ABSTRACT FROM AUTHOR]

Label-free in vivo imaging is crucial for elucidating the underlying mechanisms of many important biological systems in their most native states. However, the applicability of existing modalities has been limited to either superficial layers or early developmental stages due to tissue turbidity. Here, we report a synchronous angular scanning microscope for the rapid interferometric recording of the time-gated reflection matrix, which is a unique matrix characterizing full light-specimen interaction. By applying single scattering accumulation algorithm to the recorded matrix, we removed both high-order sample-induced aberrations and multiple scattering noise with the effective aberration correction speed of 10,000 modes/s. We demonstrated in vivo imaging of whole neural network throughout the hindbrain of the larval zebrafish at a matured stage where physical dissection used to be required for conventional imaging. Our method will expand the scope of applications for optical imaging, where fully non-invasive interrogation of living specimens is critical. A major challenge of in vivo imaging is imaging deeper, including in turbid tissue. The authors report an adaptive optics based microscope that uses coherent single scattering signal to reduce sample-induced aberrations and enable fast deep-tissue imaging of in vivo larval zebrafish brain. [ABSTRACT FROM AUTHOR]

Non-equilibrium dynamics expands our understanding on physical processes based on the conventional equilibrium physics. In particular, non-equilibrium steady states with continuous flow among them have drawn much interest related to various biochemical processes, biomolecular motors, and high-temperature quantum entanglement as well as Bose–Einstein condensates. Here we report observation of a non-equilibrium steady states of atoms achieved in a hybrid of a moving optical lattice and a surrounding cold atom cloud in a phase-stabilized magneto-optical trap. A part of atoms are localized and transported in the moving optical lattice and the rest are not localized in the lattice while trapped as a cold cloud of atoms. These motional states coexist with continuous transition between them. Our model calculations well reproduce the key features of the experimental observations including stepwise transitions, confirming the existence of a non-equilibrium steady state with characteristics of asymmetric simple exclusion process in the cold atom system. Non-equilibrium dynamics of cold atoms have recently attracted attention revealing unconventional phenomena. The authors report here the experimental observation of a non-equilibrium steady state in a hybrid trap composed of a magneto-optical trap and a moving optical lattice. [ABSTRACT FROM AUTHOR]