Fig. 5: Experimental setup of the exposure system. Inset: magnified image showing the two half-wave plates and orthogonal two-axis Lloyd’s mirror interference unit.

Here, the orthogonal two-axis Lloyd’s mirror module consists of two mirrors (X- and Y-mirrors) and a grating holder, and mirrors 1–4 act on guiding the output beam of the He-Cd laser. HWP: half-wave plate.