Abstract: A method refocuses on an optical assembly target surface, using at least one beam originating from a short-pulse optical source, having at least one optical system for focusing the beam on the surface. Refocusing occurs after learning reference conditions for which the assembly is considered as focused. A focusing signal is detected representing a time overlap of pulses between a beam reflected and a reference beam not reflected by the surface, one of the beams delayed by a delay line. The optical path on which the delay line is placed is varied, on the basis of the reference conditions, to cause the focusing signal to reach or exceed a predetermined threshold. The focus is adjusted on the basis of the path variation between the reference conditions and the conditions for which the focusing signal reaches or exceeds the threshold.

Abstract: A method refocuses on an optical assembly target surface, using at least one beam originating from a short-pulse optical source, having at least one optical system for focusing the beam on the surface. Refocusing occurs after learning reference conditions for which the assembly is considered as focused. A focusing signal is detected representing a time overlap of the pulses between a beam reflected and a reference beam not reflected by the surface and comes from the source, one of the beams delayed by a delay line, the beam optical path on which the delay line is placed is varied, on the basis of the reference conditions, to cause the focusing signal to reach or go beyond a predetermined threshold. The focus is adjusted on the basis of variation knowledge in the path between the reference conditions and the conditions for which the focusing signal reaches or goes beyond the threshold.