Abstract: Two-photon point spread functions of several tightly focused visible lasers were calculated based on the vectorial diffraction theory. The calculated result shows that the two-photon absorption region reduces with the decrease of laser wavelength. Femtosecond laser sources with visible wavelengths were employed to perform the two-photon polymerization fabrication, and the fabrication resolution and threshold were analyzed. The experimental results indicate that lower photon flux density leads to the improvement of fabrication resolution and the decrease of laser wavelength causes the reduction of fabrication threshold.

Key words: laser techniques; resolution; two-photon fabrication; polymerization threshold