Diffractive Sensor Elements for Registration of Long-Term Instability at Writing of Computer-Generated Holograms

Sensors (Basel). 2021 Oct 6;21(19):6635. doi: 10.3390/s21196635.


The research and development of methods using of the specialized diffractive microstructure sensors embedded in the pattern of computer-generated holograms (CGH) manufactured on circular and X-Y laser writing systems is discussed. These microstructures consist of two parts: one of which is written before the CGH in the field of future hologram and the second one is written during the long-term writing of the CGH. The shift between the first and second part of the microstructure is the trace of the writing errors and allows one to determine and calculate the error of CGH fabrication along both orthogonal coordinates. The developed method is based on the principle of diffraction-based overlay with 1D and 2D built-in diffractive microstructure-sensors. Mathematical modeling and results of experimental test writings of such diffractive microstructure sensors are described. The efficiency of using these types of build-in sensors for the writing errors estimation for CGHs is demonstrated.

Keywords: asphere testing; computer-generated holograms; computer-generated holograms certification; diffraction-based overlay; diffractive microstructure sensors; laser writing systems.