Calibration of an in-line digital holographic microscope

We present a calibration method that correlates in-line measurement results from a digital holographic microscope (DHM) integrated into a two-photon polymerisation system (TPP) with offline results from a high-resolution laser scanning microscope (LSM). Our findings indicate that a single calibration step for a specific polymer is sufficient to reliably monitor the fabrication of various structures. In future, this approach will make it possible to adapt the production process to the manufactured structure geometry in real time.