Light beam redistribution using computer-generated phase plates

The use of two phase plates for light-beam power redistribution is proposed. The first plate is designed so that the desired power distribution is obtained by near-field diffraction; the purpose of the second plate is the correction of the phase front. The deviation is based on ray optics, which is a good approximation in practical situations. As an example, design and fabrication of the phase plate for 1:2 branching of single-mode fibers are described. The phase plates have a computer-generated pattern and are fabricated by electron-beam lithography. Experimental verification of beam branching is presented.<
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