Patent ID: 7379172

Claim:
A method for inspecting an optical component, comprising the steps of generating a first light beam and a second light beam both having difference phases, from original light which has passed through the optical component; interfering the first light beam with the second light beam to form an interference region; setting a first linear line which connects the first center of the first light beam to the second center of the second light beam, and a second linear line which passes through the mid point between the first center and the second center, and intersects vertically to the first linear line; setting a plurality of third points on the second linear line within the interference region; setting a plurality of third linear lines which pass through the plurality of the third points and extend in parallel to the first linear line, respectively; setting a plurality of evaluation points on each of the plurality of the third linear lines; determining a distribution of light intensities at the plurality of the evaluation points for each of the plurality of the third linear lines; determining a distribution of light intensities at the plurality of the evaluation points for each of the plurality of the third linear lines; determining a frequency versus light intensity relationship from the distribution of the light intensities which is determined for each of the plurality of the third linear lines; determining a frequency versus light intensity relationship from the distribution of the light intensities which is determined for each of the plurality of the third linear lines; approximating a function to the plurality of the frequencies determined for each of the plurality of the third linear lines, and evaluating the aberration of the optical component based on the coefficient of the approximated function.