Design Of Multi-Wavelength Achromatic Transmission Sphere Based On Zoom Principle

The transmission sphere(TS) can only be used with a laser interferometer at a specific wavelength. This paper proposes a design method that can make the TS work at multiple wavelengths. First, use the achromatic form to design the TS so that it can be used at two wavelengths at the same time, and then adjust the interval between the TS's lens to make it at the other two wavelengths, so that the TS can be used of 4 wavelengths in total. Using this method, a TS with a diameter of 101.6mm and F# of 3 is designed. The final TS can work at the wavelengths of 532nm, 721nm, 660nm and 570nm, and the accuracy of the transmission wavefront at each wavelength meet measurement requirements