Polarization-independent coherent perfect absorption by a dipole-like metasurface

We show that polarization-independent coherent perfect absorption can be realized in a simple dipole-like metasurface by precisely engineering the ratio between the scattering loss γ(s) and the dissipation loss γ(l). This effect can be traced to a critical condition on the scattering matrix in a dipolar picture, which requires that the scattering and dissipation losses are equivalent, i.e., γ(s) = γ(l), at the resonant frequency f(0). This work expands the capability of metasurface in getting extreme optical properties, allowing for many potential applications.