Manufacturing and testing of a cubic SiC surface

The free surface and unrotational-symmetric surface optical elements have been applied more and more widely along with the development of optical design technology,although they are still difficult for manufacturing. In this letter,a SiC unrotational-symmetric aspheric surface whose surface equation is z=3λ(x3 + y3) (λ=0.6328 μm) has been introduced.The tilt abstraction is adopted to minimize the ma terial removal.The surface figures arc peak-to-valley (PV) value of 0.327λ and root-mean-square (RMS)value of 0.023λ.A non-null testing method based on digital mask is proposed to test this surface.The accuracy of the method is testified by the experiment of standard sphere testing.