Experimental realization of phase-conjugate optical coherence tomography.

We demonstrate phase-conjugate optical coherence tomography (PC-OCT) using a classical source of phase-sensitive cross-correlated beams to achieve measurement improvements shared by quantum OCT (Q-OCT): a factor-of-2 enhancement in axial resolution and even-order dispersion cancellation. Compared with coincidence counting used in Q-OCT, PC-OCT employs standard photodetection that results in much faster data acquisitions. This work belongs to a new class of classical techniques inspired by quantum methods that have advantages once thought to be exclusively quantum mechanical.