Pixel alignment method with double-slit interference for high-dynamic-range laser display system

• A method based on double-slit interference was proposed to achieve pixel alignment between phase-only and amplitude-only spatial light modulators, and a high dynamic range laser display system based on the phase light modulator (PLM) and digital micromirror (DMD) was constructed. • The approach presented is particularly suitable for laser display systems based on cascaded phase and amplitude spatial light modulators, especially in applications such as high dynamic range laser displays, holographic displays, and complex amplitude modulation. In the field of laser display technology, the spatial light modulator (SLM) functions as the core device for achieving display. Nevertheless, due to its inherent physical characteristics, one single spatial light modulator system has an upper limit on contrast ratio, making it arduous to meet the requirements of high dynamic range (HDR) display. Therefore, two spatial light modulators are frequently utilized to extend the dynamic range, and the level of pixel alignment between the two devices emerges as the decisive factor for system performance. In this research, a method based on double-slit interference was proposed to achieve pixel alignment between phase-only and amplitude-only spatial light modulators, and a high dynamic range laser display system based on the phase light modulator (PLM) and digital micromirror (DMD) was constructed. By calculating the relative position of the interference fringes to reveal the relative alignment state of the PLM and the DMD in the laser light path, including the translation and the inclination angles in three dimensions. Experiments results demonstrate that the method is simple to operate and can meet the pixel alignment accuracy of PLM and DMD within 21.6um.