Full-field optical coherence tomography system with a simplified dynamic focus mechanism

Abstract Loss of focus in depth due to the mismatch between the coherence gate and the focus gate is a limiting factor in the achievable high lateral resolution in optical coherence tomography (OCT). This work adapts a simplified dynamic focus method, utilising only one mechanical element to a full-field OCT configuration, and demonstrates the capability to maintain the alignment of the coherence gate and the depth of the focus gates, at sample depths of up to 4 mm while using a high numerical aperture objective lens (NA = 0.5).