Necessary conditions of physical realizability of the bifocal lens collimator

The conditions of physical realizability of one of the varieties of aplanitic lens collimators, a bifocal lens collimator, which has two points of perfect focus and do not lie on the main optical axis, are considered. Based on the relationship of the parameters specified during the design of the bifocal lens collimator (aperture size, thickness, focal length, distance from the main optical axis to the focal point, tilt of the phase front in the aperture), conditions that are necessary for the synthesis of a physically feasible collimator are formulated. The solution of this problem is based on the properties of an ellipse of equal edges and the geometry of a bifocal lens collimator. The graphic dependencies of the obtained expressions are given and analyzed. Based on this analysis, the mutual dependence of the parameters specified at the beginning of the calculation of the lens surface is determined. Systems of inequalities that establish the conditions for the realizability of a bifocal lens collimator are written. A number of restrictions on the initial parameters of the bifocal lens collimator are recorded. The fulfillment of the inequalities obtained in the article is a necessary condition for the physical realizability of the bifocal lens collimator.