Method and apparatus for imaging three-dimensional structure

A method for determining surface topology of a portion of a three-dimensional structure, comprising:

• (a) providing an array of incident light beams propagating in an optical path leading through a focusing optics and through a probing face;
• the focusing optics defining one or more focal planes forward said probing face in a position changeable by said optics, each light beam having its focus on one of said one or more focal plane;
• the beams generating a plurality of illuminated spots on the structure;
• (b) detecting intensity of returned light beams propagating from each of these spots along an optical path opposite to that of the incident light;
• (c) repeating steps (a) and (b) a plurality of times, each time changing position of the focal plane relative to the structure;
• (d) for each of the illuminated spots, determining a spot-specific position, being the position of the respective focal plane yielding a maximum measured intensity of a respective returned light beam;
• and
• (e) generating data representative of the topology of said portion.