Burmeister, FrankFrankBurmeisterZeitner, Uwe D.Uwe D.ZeitnerNolte, StefanStefanNolteTünnermann, AndreasAndreasTünnermann2022-03-112022-03-112012https://publica.fraunhofer.de/handle/publica/37556910.1117/12.908555We present an immersion hybrid optics specially designed for focusing ultrashort laser pulses into a polymer for direct laser writing via two-photon polymerization. The hybrid optics enables well corrected focusing over a working distance range of 577 ?m with a numerical aperture (NA) of 1.33 thereby causing low internal dispersion. We combine the concepts of an aplanatic solid immersion lens (ASIL) for achieving a high NA with the correction of aberrations with a diffractive optical element (DOE). To demonstrate the improvements for volume structuring of the polymer, we compare achievable feature sizes of structures written with our optics and a commercial available oil immersion objective (100x, NA=1.4).entwo-photon polymerizationrefractive/diffractive hybrid opticsultrashort laser pulserefractive index mismatchaberration correction620conference paper