The optical memory effect is a well-known type of wave correlation that is observed in coherent fields that scatter through thin and diffusive materials, like biological tissue. It is a fundamental physical property of scattering media that can be harnessed for deep-tissue microscopy or 'throughthe-wall' imaging applications. Here we show that the optical memory effect is a special case of a far more general class of wave correlation. Our new theoretical framework explains how waves remain correlated over both space and angle when they are jointly shifted and tilted inside scattering media of arbitrary geometry. We experimentally demonstrate the existence of such coupled correlations and describe how they can be used to optimize the scanning range in adaptive optics microscopes.

We present a fast method for numerically solving the inhomogeneous Helmholtz equation. Our iterative method is based on the Born series, which we modified to achieve convergence for scattering media of arbitrary size and scattering strength. Compared to pseudospectral time-domain simulations, our modified Born approach is two orders of magnitude faster and nine orders of magnitude more accurate in benchmark tests in 1, 2, and 3-dimensional systems.

In this paper, we propose a reconfigurable beam-shaping system to permit energy-efficient non-line-of-sight (NLOS) free-space optical communication. Light is steered around obstacles blocking the direct communication pathway and reaches a receiver after reflecting off of a diffuse surface. A coherent array optical transmitter (CAO-Tx) is used to spatially shape the wavefront of the light incident on a diffuse surface. Wavefront shaping is used to enhance the amount of diffusely reflected light reaching the optical receiver. Synthetic NLOS experiments for a signal reflected over an angular range of 20° are presented. A record-breaking 30-Gbit/s orthogonal frequency-division multiplexing signal is transmitted over a diffused optical wireless link with a >17-dB gain.

Wavefront shaping is increasingly being used in modern microscopy to obtain high-resolution images deep inside inhomogeneous media. Wavefront shaping methods typically rely on the presence of a “guide star” to find the optimal wavefront to mitigate the scattering of light. However, the use of guide stars poses severe limitations. Notably, only objects in the close vicinity of the guide star can be imaged. Here, we introduce a guide-star-free wavefront shaping method in which the optimal wavefront is computed using a digital model of the sample. The refractive index model of the sample, that serves as the input for the computation, is constructed in situ by the microscope itself. In a proof of principle imaging experiment, we demonstrate a large improvement in the two-photon fluorescence signal through a diffuse medium, outperforming state-of-the-art wavefront shaping by a factor of two in imaging depth.

Scattering prevents light from being focused in turbid media. The effect of scattering can be negated through wavefront shaping techniques when a localized form of feedback is available. Even in the absence of such a localized reporter, wavefront shaping can blindly form a single diffraction-limited focus when the feedback response is nonlinear. We developed and experimentally validated a model that accurately describes the statistics of this blind focusing process. We show that maximizing the nonlinear feedback signal does not always result in the formation of a focus. Using our model, we can calculate the minimal requirements to blindly focus light through strongly scattering media.