| To achieve the expansion of the He-Ne laser beam, the author firstly determines the scheme, on the basis of the zoom system design and the technical indexes. After the analysis of the optical system, the author counts the parameter of the beam expander system. With the helping of the software, named ZEMAX, the author have completed the zoom beam expander system at last.After analysising the technical indexes(the ratio of expander is from 50×to150×), the author decide to take the way of two-stage beam expander system. The first stage is refractive system, and the second stage is reflective system.Basis on the varifocal optical system, the first afocal zoom system which have three components is used as the first stage beam expander system. Through the analysis of the three components, the movement of the variator, fixed group and compensator are derived. Using the software of optical system design, named ZEMAX, the first stage beam expander system which have the magnification from 5×to 15×are designed.Basis on the analysis of the system, which are composed with two reflective mirrors, the author decide to use the Cassegrain system, which is off-axis and improved. With the theory of aberration, the author figure out the parameter,composed with eccentricity (e12,e22) and system size (α,),of primary mirror and second mirror, which compose the second stage beam expander system. Using the ZEMAX, the second stage beam expander system which have the magnification 10×are designed.After optimizing the system, which are composed with two stage, the zoom beam expanding system have designed. Through the analysis of OPD, it can be proved that the system is designed successfully.The zoom beam expanding system has simple structure, excellent performance. |
