Real-time full-field imaging through scattering media by all-optical feedback

Full-field imaging through scattering media is fraught with many challenges. Despite many achievements, current imaging methods are too slow to deal with fast dynamics, e.g., in biomedical imaging. We present an ultrafast all-optical method where a highly multimode self-imaging laser cavity is built around the reflective object to be imaged and the scattering medium. We show that the intracavity laser light from the object is mainly focused onto specific regions of the scattering medium where the phase variations are low. Thus, round-trip loss within the laser cavity is minimized, thereby overcoming most of the scattering effects. Our method can deal with temporal variations that occur on timescales as short as several cavity round trips, typically 100 ns in our laser cavity.