Design and alignment strategies of 4f systems used in the vectorial optical field generator

In this paper, the design and alignment strategies of 4f systems used in the vectorial optical field generator are described in detail. Reflection-type 4f systems were adopted due to limited spacing. Alignment patterns are designed and introduced as alignment tools so that the optical property (degree of freedom) controlled by each specific spatial light modulator section can be visualized and alignment of the 4f systems can be performed using the CCD image sharpness as the metric. In particular, blurring due to diffraction effects is minimized when the 4f system is fully aligned.