Wavefront Sensor Using Double-efficiency Quad-cells for the Measurement of High-order Ocular Aberrations

Abstract

This paper presents a discussion about an alternative layout for optical wavefront sensors, which is composed of positionsensitive detectors (PSDs) of the quad-cell type with two different sensitivity regions (i.e. quantum efficiencies). This wavefront sensor can be used in the measurement of high-order ocular aberrations, associated with the Hartmann Shack method. The proposed layout is compatible with the standard complementary metal oxide-semiconductor (CMOS) technology. It provides smaller measurement errors than conventional wavefront sensors, once the quad-cell response can be better approximated to a linear response. In this article, some characteristic project parameters are discussed based on numerical simulation results, so as to make the sensor suitable for high-order ocular aberrations measurement.

Impact of CMOS Pixel and Electronic Circuitry in the Performance of a Hartmann-Shack Wavefront Sensor

“…The average coefficient values for ocular aberrations of a population of individuals, registered by Porter et al [ 25 ], describe the deployed input wavefront. In the results displayed in the simulations of Figure 5 , the minimum number of microlenses considered in an orthogonal array was 25, in order to minimize the sampling error, assuring a reliable WF reconstruction by having enough sampling points available to represent the targeted Zernike reconstruction modes [ 30 ]. Further simulations with only 16 microlenses led to undersampling, and therefore to a significantly high reconstruction error and a less reliable reconstructed WF.…”