Phase-sensitive swept source optical coherence tomography for imaging and quantifying of microbubbles in clear and scattering media

A phase resolved system based on swept source optical coherence tomography (SSOCT) called as phase-sensitive SSOCT to detect and quantify gas microbubbles in aqueous and tissue simulated media is developed. The structural images of gas microbubbles are obtained using conventional SSOCT, while common path SSOCT was used to perform the phase-sensitive measurements. The system shows an axial resolution of 10 μ m , a phase sensitivity of 0.03 rad , an imaging depth of up to 6 mm in air, and a scanning speed of 20 kHz for a single A -line. The structural images of the bubbles show an accuracy of 10 μ m , whereas the temporal phase response show an accuracy of 0.01 μ m . Images of rapidly moving bubbles are also presented which indicate that the SSOCT could be ultimately applied for the rapid assessment of microbubbles in biofluids and tissues.