Computer-generated holographic phase shifter with liquid crystal display

Exact phase shifts are very important for phase-shifting digital holography or interferometry. Some phase-shifting methods suitable for different applications have been proposed; but most of them often require precise moving or rotating drivers. A new digital phase shifter with liquid crystal display (LCD) was proposed. In this method, the phase shifts needed in digital holography were induced by changing encodes of the computer-generated holograms (CGH) displayed on the LCD. The advantage of this method is that the phase shifts can be controlled digitally and no any precise mechanical moving or rotating element is required. Both the theoretical analysis and experimental results demonstrate the feasibility of this approach. The phase stability of the LCD as a phase shifter was studied experimentally. The experiments show that the range of the phase fluctuates is below about 0.036 rad.