Inverse Hartmann test for radius of curvature measurement in a corneal topography calibration sphere.

In this article, the use of a square Hartmann screen test to measure the radius of curvature of a corneal topography calibration test sphere is presented. The proposed technique is based on the image formation principle by specular reflection on convex reflective surfaces. Applying an inverse Hartmann test, a de-magnified virtual image (Hartmanngram) is obtained; considering their own scaled reference screen plate, a zonal wavefront retrieval approach is used and the radius of curvature obtained.

Measurement of spherical and cylindrical power in ophthalmic lenses based in the change of lateral amplification.

In this article, we present a new technique to measure spherical and cylindrical power in ophthalmic lenses. This method is based in the change of lateral amplification produced by an optical system when introducing an ophthalmic lens. Ophthalmic lens power is calculated by considering the change in image size from a reference object and its own image seen through the ophthalmic lens.

Transformation of Bessel beams by means of a cylindrical lens.

The diffraction patterns of a conical lens illuminated by plane and spherical waves have been intensively investigated. A practical method is described to transform the Bessel profile of a zero-order Bessel beam into a caustic one through the use of a combination of a conical lens and a cylindrical lens, which in turn transforms the field generated by the conical lens. The cylindrical lens was illuminated by a zero-order Bessel beam, producing a lips caustic beam.

Self-healing property of a caustic optical beam.

It is well known that Bessel beams and the other families of propagation-invariant optical fields have the property of self-healing when obstructed by an opaque object. Here it is shown that there exists another kind of field distribution that can have an analog property. In particular, we demonstrate that a class of caustic wave fields, whose transverse intensity patterns change on propagation, when perturbed by an opaque object can reappear at a further plane as if they had not been obstructed.