Direct and clean loading of nanoparticles into optical traps at millibar pressures

Nanoparticles levitated by optical fields under vacuum conditions have applications in quantum science, the study of nanothermodynamics and precision sensing. Existing techniques for loading optical traps require ambient conditions, and often involve dispersion in liquids, which can contaminate delicate optics and lead to enhanced optical absorption and heating. Here we present a clean, dry and generic mechanism for directly loading optical traps at pressures down to 1\,mbar, exploiting Laser Induced Acoustic Desorption. Our method allows rapid and efficient trapping, and is also suitable for site-selective loading of nanofabricated particles grown on a silicon substrate.