Adjustable amplitude-phase hybrid gratings: Intensity-sharing management between diffraction orders

In this Letter we propose a method for designing an adjustable amplitude-phase hybrid grating in which by relative lateral shearing of its amplitude and phase parts, the intensity share between different diffraction orders can be controlled. The method is based on superimposing two pure-amplitude and pure-phase gratings with sinusoidal or binary profiles having the same periods and lines’ orientations. It is shown that, in the diffraction of a Gaussian beam from such hybrid gratings, the intensity share of each of the diffraction orders is related to the shear value, and the amplitude of the transmission functions of the superimposed pure-amplitude and pure-phase gratings. For instance, when both of the amplitude and phase profiles are sinusoidal and the shear value between them is quarter of the period, for given values of the transmissions amplitudes of the profiles, all positive (or negative) diffraction orders are removed. We also show that, by changing the values of the transmissions amplitudes the intensity share for the higher orders can be increased. This kind of gratings might find application in optical switching and in devices requiring power sharing between different channels such as in non-mechanical beam-steering devices, in optical interconnects, and in optical fiber communication.