Simultaneous dark-bright field swept source OCT for ultrasound detection

We introduce a swept source FDOCT imaging system that allows measuring simultaneously the reflected light and scattered light (bright field) and the scattered light only (dark field) in two different channels through separate Gaussian and Bessel detection. Specular reflections can then be used to obtain knowledge about the sample time evolution with high SNR for phase analysis. Based on this configuration, we provide a proof-of principle study for resolving ultrasound pulse trains with high temporal resolution on surfaces, which potentially provides a novel phase sensitive all optical detection scheme for the combination of OCT with photoacoustic imaging.