The wavenumber linearisation without calibration device for spectral‐domain optical coherence tomography

The wavenumber nonlinearity leads to blurred reconstructed images in spectral‐domain optical coherence tomography (SDOCT). In this work, a wavenumber‐linearisation method without calibration devices is presented, based on the fact that the difference between the phases of adjacent peak and valley points is equal to π$\pi $. The theoretical model is derived, and the efficacy of the method was proven by acquiring SDOCT data from TiO2 phantom and zebrafish. The results exhibit the superior performance of our method. Compared with the linear phase‐based method, the resolution could be improved at least a factor of 2. Compared with the polynomial fitting method, the resolution could also be improved by nearly half.