| 摘要 |
<p>Interferometric method and apparatus for measuring aspheric surfaces and wavefronts by directing a spherical wavefront of known design at a wavelength λ1 at a reference sphere with known measured surface properties (17, 18) to generate a first electronic signal containing information about the optical path differences between the reference and measurement wavefronts generated by an interferometer (21, 22) and directing an aspherical wavefront of known design at a wavelength λ2 at an aspherical surface or wavefront to be tested (15, 16) to generate a second electronic signal containing information about the optical path differences between the reference and measurement wavefronts generated by the interferometer. The first and second electronic signals are analyzed and calculated therefrom as wavefront error maps W1 = W1(λ1) and W2 = W2(λ2), both of which containing wavelength dependent known design and measured errors and unknown errors due to the manufacture, material composition of the components in the interferometer, and systematic errors. Optical path length errors caused by shape errors in the aspherical surface or wavefront are determined while accounting for substantially all error sources present in the electronic signals for enhanced precision.</p> |
