Nano-optomechanics in a focused laser beam: exploration of bidimensional optical force fields
Institut Néel, CNRS, Grenoble, France
Date & Time
Thursday, June 20th, 2013
2:00pm - 3:00pm
3001 Elings Hall
Optomechanics explores the fundamental coupling between light and mechanical motion. In recent years, this research has made important advance in both understanding and manipulating the macroscopic optomechanical interactions down to the quantum level. However, the diffraction limit has so far prevented sensitive explorations of topological effects of light, accessible only at scales well below the optical waist. In this talk, I will present the recent progress obtained in the context of my PhD thesis. The nano-optomechanical setup I developed consists of suspended nanomechanical resonators placed at the waist of a focused laser beam. I will show that despite its apparent simplicity, such optomechanical configuration enables quantum-limited detection of Silicon Carbide nanowires with cross-sections that are far below the diffraction limit. I will show that our system can be operated as a ultra-sensitive vectorial probe, which we use to reconstruct the full topology of the radiation force field in a focused laser beam. I will present an advanced analysis of the topological variations of light within a highly focused laser beam, and I will show that they are responsible for strong back action effects, leading to a dynamical bifurcation in regions of strong vortical components of the electromagnetic field. Our work opens new fundamental perspectives in optomechanics, and has strong implications in both ultra-sensitive scanning probe microscopy and nano-optics.