Swept-source coherence-gated Shack-Hartmann wavefront sensor

In this report we investigate the possibility of narrowing the depth range of a physical Shack-Hartmann wavefront sensor (SH-WFS) using coherence gating technique in spectral domain. A time-domain low coherence interferometry (LCI) setup [1] has already been demonstrated capable of generating similar Shack-Hartmann spots pattern to that delivered by a conventional SH-WFS. Stray reflections are eliminated in the images due to a narrow coherence gating introduced by the interferometric technique. Hereby we present another approach by employing a wavelength tuneable light source to obtain Shack-Hartmann spot patterns with coherence gating in a 3D volume without axial scanning. Signal strength is enhanced in contrast with a conventional SH-WFS and signal to noise ratio is improved compared to the previous time-domain setup. This novel technique has the potential of providing depth resolved wavefront aberration information, which can guide better wavefront correction in adaptive optics assisted ophthalmology imaging and confocal microscopy instruments.