A technique for optical coherence tomography is provided. As to a device aspect of the technique, an imaging device 28 comprises a base 30 defining a rotation axis 32, a scanning and focusing assembly 34 mounted to the base 30 for rotation about the rotation axis 32, and a drive unit 50 for rotationally driving the scanning and focusing assembly 34 about the rotation axis 32. The scanning and focusing assembly 34 includes a focusing device 40 for focusing a beam 36 of imaging radiation to produce a focused beam 44, 44a, 44b of imaging radiation having a focus 42, 42a, 42b, a scanning member 38 for scanning the beam 36 of imaging radiation, and a controller 45 coupled to the drive unit 50 and the scanning member 38 and configured to control the scanning member 38 to cause movement of the focus 42, 42a, 42b along a predetermined trajectory 46, 46a, 46b with respect to the scanning and focusing assembly 34.
