The aim of the present work is to introduce a lens whose faces are a conical surface and a spherical surface. We illuminate this lens by a plane wavefront and its associated refracted wavefronts, light rays and caustic are computed. We find that the caustic region has two branches and can be virtual, real or one part virtual and the other real, depending on the values of the parameters characterizing the lens. Furthermore, we present a particular example where one of the branches of the caustic region is constituted by two segments of a line, one part is real and the other one virtual. The second branch is a two-dimensional surface with a singularity of the cusp ridge type such that its Gaussian curvature is different from zero. It is important to remark that for this example, the two branches of the caustic are disconnected. Because of this property and the result obtained by Berry and Balazs on the relationship between the acceleration of an Airy beam and the curvature of its corresponding caustic, we believe that using this optical element one could generate a scalar optical accelerating beam in the region where the caustic is a two-dimensional surface of revolution, and at the same time a scalar optical beam with similar properties to the Bessel beam of zero order in the region were the real caustic is a segment of a line along the optical axis.

目前工作的目的是介绍一种透镜，其面是圆锥面和球面。我们用平面波前照射这个透镜，并计算其相关的折射波前、光线和焦散。我们发现焦散区域有两个分支，可以是虚拟的、真实的或一部分是虚拟的，另一部分是真实的，这取决于表征镜头的参数值。此外，我们还提供了一个特定示例，其中焦散区域的一个分支由两条线段构成，一部分是真实的，另一部分是虚拟的。第二个分支是具有尖峰脊型奇点的二维表面，其高斯曲率不为零。需要注意的是，对于此示例，焦散线的两个分支是断开连接的。由于这一性质以及 Berry 和 Balazs 就艾里光束的加速度与其相应焦散曲率之间的关系获得的结果，我们相信使用这种光学元件可以在以下区域产生标量光学加速光束焦散是一个二维旋转表面，同时具有与该区域中零级贝塞尔光束相似特性的标量光束，而真正的焦散是沿光轴的线段。