Digital Shack-Hartmann Wavefront Sensor for toroidal surface measurement

Method for distortion correction of multi-layered surface reconstruction using time-gated wavefront sensing approach

“…Specifically, it is used to measure aberrations on the corneal surface [26] and the lens of the eye. From [4,6], a typical wavefront sensing was illustrated that the reflection of a given surface is sampled in an array form. A deviation of the points from the centre of its respective grids indicates that the reflection has taken place on an uneven surface.…”

“…The advantage of the proposed gated wavefront sensing is the simplicity of configuration and real-time processing ability for multi-layer discrete medium explicitly. Traditionally, the Shack-Hartmann wave-front sensor uses an array of microlens to dissect the incoming wave-front into segments [4] to create focal spots on a CCD array [37]. From the detection of these spots and consecutive integration of the displacements across the focal plane, the shape of the wavefront can be estimated.…”

“…It has been a severe yield limiting factor in future generation technologies due to this particular challenge. Thus, the wavefront sensing can be used for wafer inspection [1]- [4]. Raymond et al [5] used a high performance Shack-Hartman sensor to analyze the wavefront of a beam of light reflected from a silicon wafer surface.…”