Order parameters are key of various physical properties and their applications. Unlike ferroic systems with finite and measurable order parameters (such as dipole moment in ferroelectrics, magnetization in ferromagnetics, and toroidal moment in ferrotoroidics), antiferro-systems, especially antiferromagnets are much subtle for its characterization and manipulation. The order parameter in collinear AFMs, usually dubbed Neel vector, cannot be directly toggled via traditional approaches such as applying a magnetic field. Hence, how to detect Neel vector, or more radical problem, how to control Neel vector in AFMs, lies at the frontier of spintronic field. We develop an extended theory that is based on our long-term investigation of opto-mechanics to include both light absorption and scattering in AFMs recently. This could simultaneously break inversion and time-reversal symmetry of parity-time symmetric AFMs, leading to a nonreciprocal scattering interaction. Our parameter-free calculations give quite consistent results as recent experimental observations in MnBi₂Te₄ thin films. Our approach does not require the system to be exotic in topological electronics (axion insulating electromagnetic coupling as proposed before), following by the well-known Occam's razor spirit. We hope that further experiments could verify our theory. But before that, one can read our publication in Nano Letters at https://pubs.acs.org/doi/full/10.1021/acs.nanolett.5c01576.