Biological cells form complex micro-factories, driven by internal nanomotors. The latter move, interact, bump and generate coordinated forces on the membrane. Designing equivalently complex micromachines constitutes an outstanding challenge, which requires to understand how to generate work from the bottom-up. In our lab, we have developed artificial nanomotors, formed by self-propelling and asymmetric nanoparticles. The nanomotors use thermal gradients to propel in 3D, reaching velocities up to ~ 200 µm/s. Thanks to their self-propulsive dynamics, they can generate forces on microscale objects. The aim of this internship is to investigate the influence of large ensembles of nanomotors on the dynamics of a passive microbead. Due to the presence of internal energy input, the dynamics of a passive tracer is far-from-equilibrium, and expected to differ from Brownian motion. Our strategy uses photothermal heating (induced by laser) to generate propulsion, and enables spatiotemporal modulation of the activity of the bath. Based on this, the trainee will study how the dynamics of the bead can be connected to the non-equilibrium properties of the active bath, in particular in terms of macroscopic quantities such as active pressure and temperature. The goal is to extract relevant protocols to further harness a nanoscale active fluid in 3D to generate work.