Abstract: Elliptical error in the generating of toric lenses is substantially eliminated, thereby reducing the time and cost of the production of such lenses. A cup-shaped cutter wheel is swept to cut the lens in a plurality of cuts, suitably three cuts. During each cut the inclination of the cutter wheel and its displacement from the lens in a direction along the optical axis of the lens are changed. Each subsequent cut reduces the elliptical error left after the preceding cut. A computer controller, including a memory storing a table of values of angular orientations and displacements of the cutter wheel with respect to the lens for each of a series of cross curve powers (D.sub.C) which is desired to accompany each of a series of base curve powers (D.sub.B), is used to control the positioning of the cutter unit mounted on the headstock and the tailstock on which the lens is mounted for cutting so as to cut both convex (plus) and concave (minus) toric lenses with minimal elliptical error in the cross curve thereof.

Abstract: Frequency conversion, particularly tripling of coherent radiation of high intensity laser beams in the red or infrared (approximately 1.06 micrometers), is obtained at high efficiencies by operating a nonlinear optical element, such as a nonlinear crystal, at an efficiency of conversion to a first frequency that results in optimal input to the same or another non-linear optical element for efficient conversion to a second frequency over a wide range of input beam intensities. An input beam from a Nd:glass laser operating at about 1.06 micrometers can be converted to a high quality output beam of triple the frequency, about 0.35 micrometers, with an overall conversion efficiency in excess of 75%.