The effects of Gaussian beams on optical coherence tomography

The theory of optical coherence tomography (OCT) was conventionally considered as the light beams propagating in the system to be in the forms of planar waves. However, the actual behaviors of the light beams in an OCT system are more likely to be Gaussian beams. With the consideration of the light beam passing through the focal lens in the sample arm to be a Gaussian beam, we deduced the theory of OCT in an analytic form. We also simulated and analyzed the interference signals with different positions of the photodetector and the interface in the sample as well as their transverse patterns spectrally. The results were demonstrated by experiments with a Fourier-domain OCT system.