|
Phase imaging is a widely used tool in biology with clinical applications. Various phase sensitive imaging techniques exist, ranging from phase contrast microscopy to quantitative schemes such as spatial light interference microscopy and off-axis holography. Here, we discuss these techniques in terms of the Fisher information content they provide, and the resulting Cramer Rao bounds of phase measurement accuracy [1]. We introduce the theoretical framework assuming that shot-noise is the dominant source of noise, and deduce the necessary conditions required to perform optimal phase estimations. This approach brings insights to design maximally sensitive microscopes for photon-limited applications, such as high-speed measurements, or the imaging of ultra-cold atoms or fragile biostructures. We further discuss how local wavefront shaping, adapted to the sample under study, can maximize Fisher information and enable optimal phase estimations [1,2]. We observe the largest improvement when imaging thick samples and demonstrate it experimentally. [1] Fundamental bounds on the precision of classical phase microscopes, D. Bouchet, D. Maestre, J. Dong, and T. Juffmann, https://arxiv.org/abs/2011.04799 [2] Local Optimization of Wave-fronts for optimal sensitivity PHase Imaging (LowPhi), T. Juffmann, A. de los Ríos Sommer & S. Gigan, Opt. Commun., 454, 124484 (2020), DOI: 10.1016/j.optcom.2019.124484
|
