Meaning
Deviation of an actual light wave from its ideal spherical or planar shape as it passes through an optical system. A wavefront error quantifies the difference between the intended path of light and the actual path caused by imperfections in lenses or mirrors. It is expressed in units of length or fractions of the wavelength being measured.
Optical Distortion
Measurement of the shape of the wave allows designers to identify specific flaws like astigmatism or coma. The presence of a wavefront error reduces the sharpness of the image and lowers the overall contrast of the optical device. Every component in the path adds to the cumulative distortion of the beam.
Measurement Technique
Interferometry provides the high precision required to map these deviations across the aperture of the system. While a theoretical design might predict a perfect result, the actual wavefront error appears during the manufacturing phase due to polishing tolerances and material density variations. This data is used to adjust the alignment of the final assembly.
Performance Tolerance
Acceptance of a finished lens depends on whether the measured distortion falls within the specified limits for the intended application. A high wavefront error leads to a rejection of the part. It is the main metric for quality.
