Opto-mechanical force mapping of deep subwavelength plasmonic modes.

We present spatial mapping of optical force generated near the hot spot of a metal-dielectric-metal bowtie nanoantenna at a wavelength of 1550 nm. Maxwell's stress tensor method has been used to simulate the optical force and it agrees well with the experimental data. This method could potentially produce field intensity and optical force mapping simultaneously with a high spatial resolution. Detailed mapping of the optical force is crucial for understanding and designing plasmonic-based optical trapping for emerging applications such as chip-scale biosensing and optomechanical switching.