  Non-invasive and ultra-accurate optical manipulation of nanometer objects has
recently gained a growing interest as a powerful enabling tool in
nanotechnology and biophysics. In this context, Self-Induced Back-Action (SIBA)
trapping in nano-optical cavities has shown a unique potential for trapping and
manipulating nanometer-sized objects under low optical intensities. Yet, the
existence of the SIBA effect has that far only been evidenced indirectly
through its enhanced trapping performances. In this article we present for the
first time a direct experimental evidence of the self-reconfiguration of the
optical potential experienced by a nanoparticle trapped in a plasmonic
nanocavity. Our observations enable us gaining further understanding of the
SIBA mechanism and determine the optimum conditions to boost the performances
of SIBA-based nano-optical tweezers.
