An automated, interferometrically referenced scanning knife-edge beam profiler with submicron resolution is demonstrated by directly measuring the focusing properties of three aspheric lenses with numerical aperture (NA) between 0.53 and 0.68, with spatial resolution of 0.02 microm. The results obtained for two of the three lenses tested were in agreement with paraxial Gaussian beam theory. It was also found that the highest NA aspheric lens, which was designed for 830 nm, was not diffraction limited at 633 nm. This process was automated using motorized translation stages and provides a direct method for testing the design specifications of high numerical aperture optics.
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