OCT's axial 'slice thickness' does not depend on the objective — only on the source: the wider the bandwidth, the thinner the slice.
OCT is low-coherence interferometry: an interference signal only exists while the reference–sample path difference stays within the source coherence length, so the axial resolution element δz equals that coherence length (divided by n inside the medium). The objective's numerical aperture only affects lateral resolution and depth of focus — the fundamental difference from confocal microscopy, and the reason broadband SLDs are the standard OCT source.
Mind the Gaussian assumption: real flat-top or double-peaked SLD spectra produce side lobes after the Fourier transform (ghost tails), making effective resolution slightly worse than the formula. Engineering practice evaluates a Gaussian-equivalent bandwidth or applies spectral shaping. Our SLD factory reports include the measured spectrum for exactly this purpose.
Related tools: Coherence length · Spectral ripple & FSR
※ Formulas on this page assume ideal models; all device parameters shown are typical values — refer to the datasheet and the serialized factory test report shipped with each unit. For selection support, contact sales@lncetek.com.