Wave-front Coding for increased depth of field of optical systems

The limited depth of field (DOF) is a major limitation of the performance of microscopic optical imaging and analysing systems. Wave-front coding (WFC) has been demonstrated in recent years for enhancing the DOF by phase coding the aperture and post processing the taken image afterwards. Compared to other measures this is achieved without significant reduction of the amount of light and resolution of the image We show how WFC works by using a cubic phase plate beginning from design simulations to fabrication issues to the point of experimental results. We demonstrate the method of WFC for multidimensional objects with an enhanced depth of field. The phase plate fabrication as a refractive element processed by ultra-precision-milling and its characterization are presented as well as the constraints for image quality concerning resolution and noise.