We report the fabrication of micro lens using an alternative annular scanning mode with continuous variable layer thickness by two-photon polymerization after multi-parameter optimization. Laser scanning mode and scanning pace parameter are optimized to achieve good appearance. As examples of the results, a 2 x 2 micro spherical lens array with diameter of 15 microm and a micro Fresnel lens with diameter of 17 microm are fabricated. Their optical performances are also tested. Compared to the conventional femtosecond two-photon fabrication, this work provides an alternative, effective and cheap processing method for the fabrication of micro optic device that requires arbitrary shape with high surface quality and small scale.

Two-photon polymerization has been employed to fabricate three-dimensional structures using the biodegradable triblock copolymer poly(epsilon-caprolactone-co-trimethylenecarbonate)-b-poly(ethylene glycol)-b-poly(epsilon-caprolactone-co-trimethylenecarbonate) with 4,4'-bis(diethylamino)benzophenone as the photoinitiator. The fabricated structures were of good quality and had four micron resolution. Initial cytotoxicity tests show that the material does not affect cell proliferation. These studies demonstrate the potential of two-photon polymerization as a technology for the fabrication of biodegradable scaffolds for tissue engineering.