Characterization of thick and contact lenses using an adaptive Shack-Hartmann wavefront sensor: Limitations and solutions

Lens characterization is a key challenge for reliable optical and imaging techniques. Shack- Hartmann wavefront sensor (SHWFS) is frequently used as an efficient tool for characterizing optical elements. However, the aberrations arising from the incident wavefront, utilized for the characterization process, cause imprecision in the spherical power measurement. Accordingly, the aim of the present study is to construct an experimental configuration that consists of SHWFS incorporated with a deformable mirror (DM) to provide a correction for the incident wavefront aberrations which yields an ideal plane wave. Different types of thick lenses with a wide range of focal lengths and three single-vision contact lenses were tested before and after aberrations compensation and compared to the reference-based method. The comparison was based on measuring the spherical powers for the tested lenses. The results indicate that the accuracy of measurements is influenced by the incident wavefront aberrations, which has been improved by the proposed compensation system. Finally, the limitations are investigated and it was concluded that the system in its current configuration failed to accurately measure some thick lenses. This issue was solved by suggesting a compound lens correction methodology that extended the measurement range of spherical powers beyond the designated measurable range of the system.

Automated summary

Lens characterization is challenging due to incident wavefront aberrations. This study proposes an experimental configuration combining Shack-Hartmann wavefront sensor (SHWFS) with a deformable mirror (DM) to correct for aberrations and achieve an ideal plane wave. The system was tested on various lenses, and the proposed compensation system improved measurement accuracy and expanded the measurable range through a compound lens correction methodology.