LAUSR

The polarization is an important characteristic of light and plays a critical role in many natural and industrial processes. In this paper, we present an optical gradient forces actuated polarization converter based on a slot waveguide, which can convert the linearly polarized light to circularly polarized light. The working principle of presented polarization converters is that optical gradient forces deform the slot waveguide to adjust its birefringence, thus to yield desired phase shift between two orthogonal components of light. An optomechanical model with all possible mechanical boundaries is developed to solve the bending deformation of polarization converters. In which, the effective index method and dispersion relation method are used for the calculation of birefringence and optical gradient forces, respectively. The influences of the width of waveguides and the initial width of the slot on the working performance of polarization converters are discussed. It is found that these influences are independent of the mechanical boundaries. The empirical formula for describing the relation between the working power and length of polarization converters is given. This empirical formula may be helpful to design such polarization converters.