Patent ID: 8422023

Claim:
An optical coherence tomography (OCT) apparatus comprising: an interferometer having a reference arm and an object arm, said object arm providing an object beam for scanning of an object; wherein a coherence gate is determined by the optical path difference between the reference arm and the object arm for returning an OCT signal from the object; said interferometer including optical components mounted on a common translation stage for scanning an object with said object beam; said optical components being configured to bring said object beam to a focus; said translation stage being displaceable towards and away from said object to permit scanning said object in an axial direction; said optical components being configured on said translation stage to permit displacement of the translation stage in said axial direction with said optical components remaining in a fixed relationship; wherein said optical components are configured to maintain said coherence gate in approximate coincidence with said focus during axial displacement of said translation stage with a variable error ε between said coherence gate and said focus; and wherein an initial error ε 0 in a reference plane is set at a value computed to reduce the variable error ε during axial and transverse scanning of the object over an axial range of interest taking into account the refractive index of the object and its curvature.