The influence of the duty ratio of the photomask for the formation of a gradient PPLN

Abstract

For experimental studies of the formation of the domain structure in lithium niobate gradient was used oriented crystalline plate thickness up to 1.5 mm (the so-called z-cut, i.e. the chosen axis of the crystal perpendicular to the plane of the plate). To study the effect of duty ratio of the photomask and the system of liquid electrodes on process of formation of regular domain structures in gradient plates of lithium niobate was used a photomask in the form of eight lanes with a width of 500 μm, length 2.5 cm, total period of 30 μm and a duty cycle between 0.2 and 0.8. Analysis of the pulse shape of repolarization and the electrical current flowing in the polling and analysis of domains after etching in acid mixtures showed that the presence of a composition gradient in the crystal plates of lithium niobate optimum combination of duty cycle in the photomask is between 0.3 to 0.4. With these values of duty cycle tracks the photomask in the gradient plates of lithium niobate significant and massive violations of the period of the domain structure, due to the different speeds of growth of domain walls depending on the composition, is not observed.