Dual-reference full-range frequency domain optical coherence tomography

It has been shown that frequency domain optical coherence tomography (FD-OCT) systems achieve higher sensitivities compared to time domain OCT systems. However, the obscure object structure due to the mirror image generated by the Fourier transform is one of the main problems in FD-OCT. We designed and developed a novel full range FD-OCT system that we refer to as the dual-reference full-range FD-OCT (DR-FDOCT) that enables doubling the imaging depth by removing mirror images generated from the Fourier transform of the detected real-valued spectra. The DR-FDOCT system enables full-range imaging without any loss of speed and is less sensitive to phase errors generated by involuntary movements of the subject than the other established full-range OCT systems. The reason is because it uses two signals with a phase difference of pi/2 obtained simultaneously from two reference arms to remove mirror images.