General description of image formation/transformation in optical coherence tomography using K-space approach: numerical demonstrations without the need of conventional paraxial approximation or Gaussian beams

Abstract

Assuming the most popular method of OCT-scan forming based on plane-parallel scanning of the illuminating beam and co-located illuminating/receiving apertures, we present rigorous general model using the K-space approach in which the spectral representation is used to describe both the axial and lateral structure of the illuminating/received OCT signals. According to the basic principle of OCT operation, similarly to the majority of other models OCT-image formation, the presented approach relies on the ballistic backscattering (first-order Born approximation) of the illuminating light. The assumption of single scattering is the main limitation of the model, whereas in other aspects the developed approach is rather general. It can be realized without the need of conventional paraxial approximation and unlike many models based on the use of Gaussian beams it can be applied to arbitrary beam profiles. We present instructive examples illustrating the main features/advantages of the proposed general K-space-based expressions for OCT-signal formation/transformation. The derived general expressions, in particular, are used to reveal the background assumptions implicitly used to derive the earlier known expressions for digital refocusing of OCT-images formed by highly focused beams. We also demonstrate the possibility of digital “super-refocusing” which does not yet overcome the diffraction limit, but makes it possible to enable the lateral resolution several times better than in the initial physical focus.
The study was supported by the Russian Science Foundation grant No. 22-22-00952




File with abstract

Speaker

Vladimir Y Zaitsev
Institute of Applied Physics RAS
Russia

Discussion

Ask question