Optical spot geometric parameter determination using calibration targets

Abstract

A method, system and computer program product for determining a geometric parameter of an optical spot of a light beam are disclosed. A method comprises: providing a calibration target, the calibration target including a systematic variation in a parameter; measuring the calibration target with respect to the systematic variation using the light beam to obtain a plurality of measurements; and analyzing the measurements and the systematic variation to determine the geometric parameter of the optical spot.

1 . A calibration target for measuring a size of an optical spot of a light beam, the calibration target comprising:
 a first portion, a dimension of which in a first axis systematically decreases along a second axis;   a second portion; and   a third portion;   wherein the second portion and the third portion extend along opposite sides of the first portion and are separated by the first portion in the first axis, and include a material of different optical response than that of the first portion.   
   
   
       2 . A calibration target for measuring a level of symmetry of an optical spot of a light beam, the calibration target comprising:
 a gradient in a parameter along an axis of the calibration target, the gradient being a function of the axis, and including one of:   a continuous gradient from one end of the calibration target to another end thereof in the axis; or   a switch point in a given point of the calibration target in the axis between two sub-gradients, one of the two sub-gradients being an ascending gradient and the other being a descending gradient.