Novel industry ready sensors for shape measurement based on multi wavelength digital holography

The advance of industrial manufacturing processes of high-precision components with fast production cycles poses great challenges for modern measurement techniques both in terms of accuracy and measurement speed. A promising candidate to satisfy both of those requirements is digital holography (DH) [1-9]. DH is a non-scanning optical measurement technique that intrinsically allows for resolution in the range of nanometers or even below on specular surfaces [2]. So far three major challenges have prevented DH from being applied in a wide variety of applications. The first is the limited axial measurement range given by half the wavelength that is used for measurement. The second is the fact that on rough surfaces speckles overlay the measured light field and prohibit direct access of the phase of the diffracted light field. The third challenge is posed by the time consuming numerical methods that have to be used to reconstruct digital holograms consisting of numerous sampling points, i. e. pixels.