Design, fabrication and evaluation of a hybrid diffractive-refractive achromat

There has been extensive recognition that it is feasible to correct simultaneously the spherical aberration and longitudinal chromatic aberration of a singlet lens by forming a diffractive element on one of its surfaces. Despite the widespread recognition of the feasibility of this design approach there has been little experimental confirmation of the performance improvements which can be expected. The author presents a specific example and describes the design technique, fabrication method and test results. The main benefits and drawbacks of this design approach are discussed