Far-field diffraction pattern of a nonideal retroreflector for polarized light with an oblique incidence.

The far-field diffraction pattern (FFDP) of a corner cube retroreflector (CCR) determines the energy of a retroreflecting beam in some applications including laser ranging, optical communication, and satellite orbit calibration. The FFDP of an imperfect CCR is investigated analytically for the non-normal incidence of a polarized light beam. We first derive a complex amplitude of a retroreflecting beam in relation with multiple parameters including the errors of dihedral angle, flatness in a CCR, and polarization property of the CCR. Then a theoretical expression of the FFDP for a nonideal CCR is deduced as a function of multiple parameters by introducing the complex amplitude into a simplified Kirchhoff's diffraction equation. Some numerically simulated results of the FFDP are presented to give a visual illustration of the relationship between the FFDP and these parameters. Our findings suggest that a strong correlation between the FFDPs and multiple factors comprising the manufacturing errors, the polarization states, and the incident angles of the input beam as well as whether the reflecting faces of the CCR are coated or not. The FFDPs can be efficiently controlled by allocating the magnitudes of these factors. Moreover, experimental verification of the FFDP is also developed for a nonideal CCR coated with silver film on the reflecting faces at a non-normal incidence. The proposed mathematical model potentially offers beneficial ingredients towards optimizing design of a CCR by considering both the manufacturing errors and incident conditions of the input beam. (C) 2020 Optical Society of America