Design of Multi-Wavelength Diffractive Lenses Focusing Radiation of Different Wavelengths to Different Points

Abstract

We propose a method for calculating the so-called multi-wavelength diffractive lenses (MWDLs) intended for separating and focusing the radiation of L given wavelengths to L given points located in a certain plane perpendicular to the optical axis. The method is based on minimizing the objective function characterizing the deviation of the complex transmission functions of the MWDL from the complex transmission functions of diffractive lenses focusing the design wavelengths to the given points. In the method, the MWDL calculation is reduced to a set of independent pointwise optimization problems, each of which describes the calculation of the MWDL microrelief at one point. The presented results of the numerical simulation of the designed MWDLs confirm high performance of the proposed method. The numerical simulation results are confirmed by the results of experimental investigations, including the fabrication of MWDLs using the direct laser writing technique and the study of the MWDL operation in an optical experiment.

Keywords

• diffractive lens
• scalar diffraction theory
• Kirchhoff integral
• lens design method