J. Eur. Opt. Society-Rapid Publ. 22, 3( 2026) 29
Figure 5.( a) Intensity record by employed white-light interferometer system.( b) Surface residue fit DS z from extracted topography via WLI system. Only features with a magnitude bounded by k are presented.( c) Recorded irradiance distribution from freeform lens fabricated directly on top of LD system in accordance to the process described in Section 3. attributed to the utilized fabrication parameters and development process, with material shrinkage representing a significant portion of these contribution. Following, we measured the irradiance distribution generated by the manufactured freeform lens. This was recorded with a CMOS camera in close proximity to the LD sample, for which the obtained irradiance map is presented in Figure 5c. From the recorded map, a distorted fringe pattern in comparison to the target one can be recognized, with higher intensity values obtained towards the domain’ s boundary. Such a distortion is caused by the employed a x and a y values which were directly taken from the manufacturer datasheet and were not extracted from intensity measurements as part of the followed process. Nevertheless, despite all mentioned factors, the pattern presented in( c) still preserves most of the fringe-like structure from the intended target distribution. From the Euclidean distance function difference Du ff shown in Figure 2c with an RMS value of 345 nm and the results presented above in Figure 5, it can be concluded that the generated freeform surface design is well resolved by the employed 2PP fabrication process. Based on these results, we believe that the presented design and fabrication pipeline represents potential advantages for the realization of compact micro-optical freeform lens systems, benefiting from the flexibility offered by both, the employed GJE based design technique and the two photon polymerization based fabrication process.
5 Conclusions
In this work we have demonstrated the feasibility of combining novel inverse design algorithms with the micro fabrication capabilities offered by two photon polymerization. The presented integrated engineering pipeline benefits from the developments in both fields and serves as an important bridge between advanced design techniques and cutting edge micro fabrication technologies, enabling in this form, the further development of complex freeform surface based micro-optical systems.
Funding
This work was funded by the German Research Foundation( DFG) – project number: 537519988.
Conflicts of interest The authors declare no conflicts of interest.
Data availability statement
Data underlying the results presented in this paper are not publicly available at this time but may be obtained from the authors upon reasonable request.
Author contribution statement All authors contributed equally to this work.
References
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