| Contents |
| Fluctuations have been widely studied for small systems composed of a limited, small number of particles. Fluctuation relations or theorems describe the non-equilibrium statistical behavior of such systems and apply on microscopic as well as macroscopic scales. In large systems fluctuations play an important role if chaotic behavior appears or inverse problems like in photo- or thermoacoustic imaging have to be solved. Then the spatial resolution turns out to be limited by fluctuations if real finite sized detectors are used.
Detector arrays enable parallel detection for faster photoacoustic imaging than by moving a single detector. Spatial over-sampling is scanning with a step-size smaller than the size of the detector element and is possible only for a moving single detector. If the reconstruction is performed assuming point-like detection this over-sampling brings no advantage. For image reconstruction methods which can take the finite size of real detectors into account, this spatial over-sampling makes sense because it reduces the blurring significantly. The effect of step size on the reconstructed images is systematically examined using simulated and experimental data. |
|