Full-field swept-source optical coherence tomography with Gaussian spectral shaping

A swept source system was realized in the wavelength range of 810-875 nm with the combination of a broad-band superluminescent diode (SLD) and an acousto-optic tunable filter (AOTF) as a frequency-tuning device. SLD has two spectral centers at 820 nm and 845 nm with spectral bandwidth (FWHM) of around 40 nm. Gaussian spectral shaping was performed onto the original SLD spectrum while reconstructing OCT images for various test samples such as onion slice and fingerprint impression taken on a glass substrate. As a pulse can be considered a Gaussian distribution of frequencies, spectral shaping yields sharper Fourier peaks. Application of Gaussian spectrum facilitates in precisely locating the reflective boundaries within the sample that results in improved OCT images.