Integration of nanophotonics with micromechanical, biological, and chemical systems can miniaturize the reference samples for SI traceable calibration. However, an efficient conversion between photonic modes and free-space beams remains a main hurdle due to a gigantic mode mismatch (10(6) times in modal area). Here, we report an extreme mode converter realized on a photonic chip, which enables projecting a 160-micrometer wide Gaussian beam in free space by a sequential mode expansion from a waveguide to a slab mode and then to free space using an apodised grating. The design can be easily adapted for visible, telecom, and UV wavelengths.