Study On The Point Spread Function In The Point Scanning Imaging High Resolution Opitical Microscope

In recent years, the high-resolution optical microscope whose resolution is improved constantly develops rapidly. The resolution is affected directly by the point spread function(PSF) of the high-resolution optical microscope, especially PSF of the point scanning imaging high resolution optical microscope. In this paper, the PSFs of the point scanning imaging high resolution optical microscope are studied, and a model which can be applied to our STED system is built. So the theoretical analyses are verified. Main research achievements of this paper are as following:1 The expressions of the illumination PSF are deduced in the high-resolution optical microscope with one and three kinds of mediums. According to these expressions, a calculation model is set up. Then the effects of the polarization of incident light, numerical aperture(NA) and the refraction index of the medium on the illumination PSF are discussed by taking advantage of this model.2 The expressions of the detection PSF are deduced in the high-resolution optical microscope with one and three kinds of mediums. Combining the detection PSF and the illumination PSF, a calculation model of the point scanning imaging high resolution optical microscope is set up. Then the effects of the methods of detecting the signal, the orientations of the dipole and the pinhole on the illumination PSF are discussed by taking advantage of this model.3 The two-dimension and three-dimension hollow light spots are generated by phase modulation and polarization-phase modulation. Comparing with these light spots, the better two-dimension and three-dimension hollow light spots are obtained.4 The STED microscopical system is set up by ourselves. The key technologies of the STED system are studied, and the components of the STED system are introduced from the point of view of the high-resolution and high signal to noise ratio.5 In the STED system, the measurement of the PSFs, the focusing spot imaging of the azimuthally polarized beams and radially polarized beams, a comparison between focusing spots with different NAs, and a comparison between focusing spots with mismatch of refraction index are completed. The STED super-resolution experiment is realized. In the course of STED super-resolution experiment, a hollow light spot is obtained and the superposition of the exciting beam and depleting beam is realized.