Simplified dynamic focus method for time domain OCT

A new optical arrangement for performing dynamic focus in time domain optical coherence tomography (OCT) is demonstrated. Unlike previously reported schemes which require mechanical coupling of the object and reference arms, this method is confined to the object arm only and therefore does not impose design constraints on the OCT system layout. The scheme is tested on a high lateral resolution OCT system (NA = 0.13) and it is shown that the effective depth of focus is extended from 200 mum to better than 2 mm. The optimum correction is for media with a mean refractive index of 1.4.