Research of aberration characteristics of conicoidal conformal optical domes

Most conformal optical system designs concentrate on the researches of ellipdoidal domes. However, ellipsoidal domes are not the best ones which possess excellent aerodynamic performance among conicoidal conformal domes. This paper investigates the aberration characteristics of conicoidal conformal domes. For the purpose of the study, different types of infrared conformal domes, including ellipsoidal domes, parabolic domes and hyperbolic domes, with the common fineness ratio of 1.0 and an index of refraction of 2.25 are modeled by mathematical computation. To investigate the dynamic characteristics of the on-axis aberrations, the curves of third order fringe Zernike polynomials of the domes across field of regard are obtained by decomposing the incident wavefront at the exit pupil. The Zernike aberrations across field of view are also achieved to investigate the varying characteristics of off-axis aberrations. To find the similarities and difference between spherical domes and conformal domes at both field of regard and field of view, also make the foundation for optical design, spherical domes and defocused spherical domes are modeled for reference researches. The changing rules and the features of the aberrations among different types of conicoidal conformal domes are drawn as conclusions at the end of the paper.