Laser pulse distance measurement in real time (> 100MHz)

Fast and precise control of processing depths between the laser head and the workpiece limits the process speed of a variety of potential micro-laser processing operations for ablation, cutting or tructuring. This reduces efficiency. Current measurement methods, based on white-light interferometry or optical coherence tomography, achieve scan rates in the hertz up to kilohertz range - characteristically after machining has been completed or in time-average.

To accurately modulate or interrupt exposure, many applications require a shot-to-shot monitoring in real time. Wherever irregular inhomogeneous materials (e.g., organic structures or fiber-reinforced components) are processed with high precision, compromises between accuracy and operating speed limit process efficiency. Particularly high demands arise especially in medical eye treatment and skin ablation, but also in battery or solar cell production, where electrical insulation must be ablated in a defined manner.