  Three-dimensional (3D) direct laser writing is a powerful technology to
create nano- and microscopic optical devices. While the design freedom of this
technology offers the possibility to reduce different monochromatic
aberrations, reducing chromatic aberrations is often neglected. In this Letter,
we successfully demonstrate the combination of refractive and diffractive
surfaces to create a refractive/diffractive achromat and show, to the best of
our knowledge, the first refractive/diffractive apochromat by using DOEs and
simultaneously combining two different photoresists, namely IP-S and IP-n162.
These combinations drastically reduce chromatic aberrations in 3D printed
micro-optics for the visible wavelength range. The optical properties, as well
as the substantial reduction of chromatic aberrations, are characterized, and
we outline the benefits of 3D direct laser written achromats and apochromats
for micro-optics.
