Design Of Variable Light-sheet Illumination System Based On Zoom Principle

The light-sheet illumination microscope is a new fluorescence microscope,whose illumination light path is perpendicular to the fluorescence detection axis.When a lightening beam through the cylindrical lens,it forms a thin and uniform sheet beam in a certain range.The light-sheet illumination is fast and it has weak phototoxicity,thus it is suitable for the three-dimensional imaging of living tissue and the long time real-time imaging,which can get the real-time dynamic of cell and subcellular level.Currently,the light-sheet illumination microscope needs to change the whole system when observing the different size samples,which not only brings great inconvenience to the analysis,but also increases the cost.In order to solve the problem,this paper designs the beam expansion system or the illumination lens in the light-sheet illumination system by using the zoom method,and realizes the observation of different size samples without changing the light-sheet illumination system.The main contents of this paper are as follows:First,according to the size of the observed sample,the thickness of the variable light-sheet is set to range from 0.8?m to 4?m and 4?m to 40?m.The two initial zoom structures of the variable light-sheet illumination system are obtained by Gauss solution,and then the initial structures are optimized respectively.Then,the 10 times beam expanding system is combined to a light-sheet illumination system for optimizing,the thickness and uniformity of the YZ and XY plane for the light-sheet are analyzed.At the same time,a tolerance analysis is made for it.The 5 times zoom objective lens system based on the thickness of light-sheet is optimized and the thickness and uniformity for the light-sheet are analyzed.The simulation results show that the optical sheet thickness of the 10 times beam expanding system and the 5 times zoom objective lens all meet the design requirements.In the optimization process of the combined system,the YZ plane illumination uniformity of the low,middle and high expansion ratio of the 10 times beam expansion system can reach to 0.65,0.4 and 0.61 in the 60% light height area,respectively.The light-sheet with low and middle beam expansion has good uniformity in the whole field of view,which is beneficial to observe the samples.Tolerance analysis shows that within a relatively wide tolerance range,the thickness of the light-sheet for 1 times is less than 15% of the design,and the maximum change is less than 6% at 6 times and 10 times expansion ratio.The change in thickness of the light sheet is small,ensuring the uniformity ability of the light sheet.