Fast converging iterative wavefront sensing for scatter compensation in multi-photon fluorescence microscopy

Abstract

Adaptive optics can increase the imaging depth of nonlinear scanning microscopy by compensating for wavefront aberrations introduced by the sample using a spatial light modulator. Recent developments focus on the compensation of multiple scattering for deep tissue imaging. In this regime, sensorless iterative wavefront measurement schemes are often used due to their simplicity and robustness. Recently, we proposed such an iterative scheme, which we named ‘Dynamic Adaptive Scattering compensation Holography’ (DASH), and an even more powerful variant for complex modulation, c-DASH. The concept of DASH has some advantages over other iterative wavefront sensing strategies: it works for any aberration strength and converges in fewer measurements. Here, we present several improvements to the DASH concept that further accelerate its convergence and increase its feasibility for arbitrary scattering strengths. We demonstrate the impact of our improvements through numerical simulations and two-photon excited fluorescence microscopy experiments on synthetic scattering masks and genetically labelled endothelial cells in a mouse lung tissue. In simulations, we further verify that the optimised c-DASH can find a correction pattern through all considered aberration modes in a little more than a single measurement iteration, making it one of the fastest converging iterative wavefront sensing methods available. © 2025 The Author(s). Published by IOP Publishing Ltd.