In order to compress the beam divergence angle and reduce the energy density, beam expansion system is widely used to expand the beam in laser system. Cylinder beam expander belongs to one-dimension expander, which expands the laser beam in only one direction (X direction or Y direction), a refraction cylinder expander whose beam diameter is 180mm×120mm and magnitude ratio is 12 is designed in this paper, the working wavelength is 1058nm. To solve the problem of inequality of the working wavelength and the testing wavelength, compensation method of using parallel plate to test the system aberration is proposed. By rough grinding、precision grinding、polish and the system grinding, the final system aberration is 0.24λ(peak-valley value)
We present a method to measure the radius of curvature of a concave conic asphere. By analysis the central area of the asphere, we can measure the radius of an arbitrary point in the central area instead of the vertex of asphere. In the procedure, we firstly adjust the interferometer until the interferogram of the central area approach nulls, then put the laser tracker ball at the beam focus of the interferometer and move the tracker ball to touch the central area of the aspherical surface to get the two positions. With these measurement data, we can calculate the radius of curvature of the aspherical vertex and its uncertainty.
With the development of the fabricating and testing technology, the large optical system is widely used in more and more
fields, the diameters of the convex aspheric mirrors are also becoming larger, generally the test of the large convex
aspheres is much more difficult. It is always urgent to research and develop new fabricating and testing technology of the
large convex aspheric components. In this paper we make a comparison of the advantages and disadvantages of the
current test methods, at this basis another test method for the large convex aspheres–aspheric test plate method is given.
The principle and test setup are explained detailedly. Using ZEMAX software we design and simulate the test plates and
the wavefront error is better than 1/50 λ(PV).