Optical coherence tomography (OCT) is an emerging, near-infrared imaging and microscopy technique capable of micrometer-scale resolutions within living biological samples. Being a noninvasive imaging technique that has resolution on the order of several microns, OCT has been demonstrated in a wide range of medical, surgical, and biological applications.  Spectral-domain OCT (SD-OCT) shown above achieves better signal-to-noise ratio (SNR), higher frame rates, and greater phase stability than predecessor time-domain OCT (TD-OCT) systems.