Calibration-free B-scan images produced by master/slave optical coherence tomography

We report on a novel method to produce B-scan images in spectral domain optical coherence tomography (SD-OCT). The method proceeds in two steps. In the first step, using a mirror in the sample arm of the interferometer, channelled spectra are acquired for different values of the optical path difference (OPD) and stored as masks. In the second step, the mirror is replaced with an object and the captured channelled spectrum is correlated with each mask, providing the interference strength from the OPD value used to collect the respective mask. Such a procedure does not require data organized in equal frequency slots, and therefore there is no need for resampling as practiced in the conventional fast Fourier transform (FFT)-based SD-OCT technology. We show that the sensitivity drop-off versus OPD and the quality of B-scan images of the novel method are similar to those obtained in the conventional FFT-based SD-OCT, using spectral data linearly organized in frequency.