Optical EngineeringStructural design of doublet lenses with prespecified aberration targets
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The authors present a systematic approach for the structural design of doublet lenses in accordance with a prespecified set of Gaussian parameters and primary aberration targets. This approach obviates the need for heuristic selection of glasses for the constituent lens elements. An identical approach is implemented for the structural design of both cemented and broken contact doublets. The optimization procedure is the well-known least-squares method. For facilitating convergence a second-derivative damping technique is utilized. Constraints are taken care of by suitably defined continuously differentiable penalty functions that are treated as pseudoaberrations in optimization. A strategy for dynamic weightage of the components of the defect function is devised for overcoming stagnation at the local optimum in the immediate neighborhood of the starting point. The strategy is also effective in constraining the glasses of the constituent elements of the doublet within the permissible glass domain. Some illustrative examples are given.