Figure 2
An example of quantitative experimental results for Au NP of size 250 nm.
(a) The power spectral density of NP positions along x (red) and z (blue) axis and the black curves denote the fit of the data with Lorentzian function29,30,31. The dotted curve shows the power spectral density profile for the trapping beam directed on the camera without a trapped NP. (b) The probability density of NP occurrence along x (blue) and z (red) axis. 
and full curve denote measurement and its fit with Gaussian density distribution 
, respectively. (σx = 60 nm and σz = 410 nm) (c) Images of a NP of size 250 nm for different NA of the trapping beam and corresponding shift of its longitudinal stable position plotted together with NP position standard deviation (red errorbars). For more details see Methods.
