Application of High-reflectivity Non-periodic Sub-wavelength Gratings with Small-angle Beam-steering Ability in Fabry-Perot Cavity

An axisymmetric high-reflectivity non-periodic sub-wavelength gratings (SWGs) with small-angle beam-steering ability for reflected light is presented, and it brings a new characteristic of flexibly controlling the width of oscillation optical field for the improved Fabry-Perot (F-P) cavity which based on it. By designing the structural parameters of SWGs, both high reflectivity and beam steering can be implemented. By controlling the beam-steering angle and the cavity length, the width of oscillation optical field in the improved F-P cavity can be controlled. The properties of controlling the width of oscillation optical field are numerically investigated by the finite element method (FEM). Simulation results demonstrate that the width of oscillation optical field of the improved F-P cavity can be effectively controlled by the cavity length and the steering angle.