Research Of Spatial Light Modulationg On Confocal System With Micro-lens Array

Array-based focal microscopy has been the hot topic of the online quick inspection and measurement such as biomedicine, microstructure processing for its efficient and collateral scanning ability. However, because of the limit of the microstructure optical elements, the interval of lenticules array is about 100 um in order to avoid coupling and overlying effect. Besides, because the numerical aperture of lenticules is quite small, and the focusing characteristic is low, axial detection ability is severely reduced. In recent years, spatial light modulator can adjust the phase position and amplitude of light beam without changing optical system, which highly increases flexibility of system design. This topic uses spatial light modulator to change and adjust the light beam of array-based focal system to realize efficient and quick scanning。It used to replace light filters to realize the adjustment of detection space focousing fieldThe following is the main topics of this thesis:(1) Model of infinite conjugate distance confocal imaging system is proposed. It is theoretically analyzed the array-based confocal imaging theory and the influence of numerical aperture of collective objective lens to system axial resolution in the infinite confocal system.(2) Design the construction of blazed grating: by changing its configuration parameter to control light deviation; add array-based confocal microscopy imaging system, in order that it can scan not only in large-scale, but also densely scan in small-scale;(3) Design the construction of phasic light filter: put liquid crystal spatial light modulator in the detection arms of confocal system, under the condition of without changing the pinhole position, realize defoucs detection, the axial resolution is enhanced by using difference method.(4) Analyze the influence factors of characteristics of phase modulation in liquid crystal spatial light modulator. Measure the characteristics of phase modulation of LCSLM by Twyman Green’s interferometry and process collected images by Fourier’s transform method. Finally, establish a related experimental platform. The result of the experiments shows that the maximum phasic modulated quantity of LCSLM is more than PV value of the phasic modulated quantity is less than 0.04 rad, and the standard deviation is less than 0.011 rad. The deflection angle of blazed grating is measured, and the result shows the influence of the facula spots’ shifting to deflection angle is less than 0.028 mrad, and the deviation between measured value and theoretical value is less than 2%. Combined with microlens array, the maximum scanning range of focal spots array is 19.88μm and the minimum scanning interval of focal spots array is 4.63μm, corresponding to the maxmum beam deflection angle is 14.5 mrad, and the minimum angle is 3.4 mrad. Shifting focus effect is realized by LCSLM simulating phasic light filters, and axial resolution is increased by 80%.