Black holes and neutron stars (compact objects) attracting matter from their surroundings are known to launch continuous jets of matter and energy that are released at close to the speed of light, but the physical process of jet formation is, after 30 years of research, still poorly understood. We (both myself and members of the host institution) have recently and independently identified the signature of the magnetic field close to the base of these jets for the first time, via optical/infrared polarimetric observations of these objects. The magnetic field structure is found to be highly variable on short timescales (minutes to seconds or less), and data that provide polarimetry at moderate (minutes to seconds) and fast (less than seconds) time resolution are required to investigate the properties of the jets. Careful analysis of new data (some of which have already been acquired), adopting new, novel techniques will provide tight constraints for models and simulations of jet formation and acceleration, finally helping to answer the question 'how do compact objects launch relativistic jets, and how much energy do they release into space?'. The results will be applicable to jets launched from X-ray binary systems in our galaxy (microquasars), supermassive black holes at the centres of galaxies and gamma-ray bursts, all of which harbour compact objects. I wish to define and exploit this brand new field in astrophysical research by combining my experience and knowledge of jets from compact objects with the expertise of rapid variability and polarization of compact objects by several scientists in the host institution, advancing my skills and expertise. Defining and pioneering this new research field at the host institution is essential for my career development and will set up the perfect path towards a tenure track position.