Total internal reflection electro-optic modulator for multiple axis and asymmetric beam profile modulation

摘要

The total internal reflection modulator has an electrode array distributed across an area of the reflecting surface of the electro-optic material. The electrode array has multiple sets of electrodes forming an outer rectangle interdigitated with at least one reference set of electrodes forming a inner diamond. A diamond-shaped area with no electrodes is preferably symmetrically within the inner electrodes of the electrode array on the reflecting surface. The uniform voltage difference between the electrodes and the varying lengths of the electrodes creates a fringe electrical field in the electro-optical material and an optical phase grating to diffract the incident light on the reflecting surface. The zero order nondiffracted light becomes the output beam. The optical phase grating will control the incident beam's optical profile at the modulator (near field) and hence the imaged spot size at a focus at the image plane (far field).PPAlternatively, the total internal reflection modulator can have a diamond-shaped interdigitated electrode pattern within a rectangular shaped area with no electrodes. Using Schlieren optics, the non-zero order diffracted beam becomes the output beam with a modulated optical beam profile.