Amplitude-response matrix (ARM) expressed in the xyz-basis at a wavelength of 820 nm for a converging beam of light with an f-number of 61.3 that reflects off gold at an angle of incidence of 45°. The panels in the first and second (third and fourth) columns show the amplitude (phase) of the central 500 μm × 500 μm of the ARM elements. The positive x- and y-directions are upward and to the left, respectively. The values of the color maps are different among the panels in the first and second columns.