Electromagnetic optimization of multilevel diffractive elements by use of the wavelet transform

We present an optimization algorithm for the design of multilevel diffracti ve optical elements in the electromagnetic domain. The method uses the wave let transform to parameterize the diffractive optical elements according to a set of coefficients that corresponds to a multiresolution basis. Both lo cal and global optimizations can be performed within a single algorithm. A design example consisting of the optimization of a two-dimensional millimet er-wave diffractive lens over a 10% bandwidth is presented. (C) 2000 Optica l Society of America OCIS codes: 050.1970, 260.2110.