Phase engineering in overlapping lattices of polarization singularities

Abstract

In interference-based photonic crystal generation, invoking defect sites in lattice structures similar to the introduction of point defects such as color centers or vacancies in crystal lattices is normally difficult. The phase engineering method combined with overlapping of lattice fields can be useful in realizing exotic lattice structures. In this paper, we show the generation of tunable vector lattice fields by controlling the phase shifts between two overlapping lattice fields. Further, this concept is extended to polarization-structured lattice fields. A Fourier filter-based experimental technique is used to realize all the desired vector fields experimentally. By introducing a spatial light modulator and aq-plate in the Fourier filter-based setup, phase and polarization engineering is achieved. The working principle of this method is elaborated in this paper. Simulations supported by experimentally realized lattice fields are provided to validate the study. Such tunable vector fields can be useful in polarization-based structured illumination microscopy, realizing periodic potential landscapes for trapping and so on.