Design and testing of a novel microscopic photon correlation spectrometer with higher accuracy

Abstract

A novel microscopic photon correlation spectrometer has been designed and developed in order to employ photon correlation spectroscopy to investigate dynamic properties within a microscopic volume. It shows a spatial resolution scale of about 0.5 micrometres and a relaxation timescale of milliseconds. The variance of the scattering vector is less than 5% even at a smaller scattering angle. Furthermore, a standard performance test using 94±13 nm polystyrene latex beads has been performed on the apparatus. The autocorrelation function value at the first channel is higher than 0.8, that indicates a higher signal-to-noise ratio and a good coherent detection. CONTIN analysis gives the latex beads size as 94±2 nm. Different angle scattering results give the translation diffusion coefficient (4.57±0.08)×10-8 cm2 s-1 at 293.15 K, that agrees with the theory very well. Besides, scattering spectroscopy using different pinhole sizes determines the optimized configuration for the spectrometer with higher accuracy. All these document that the designed system works much more accurately than previous systems and may probe dynamic information from different local sites of a single living cell non-invasively.