Maximum wavelength-normalized spatial GH (top) and IF (bottom) shifts as a function of wavelength at an angle of incidence θ of 45° and 70° for reflection off gold, silver, and aluminum. The legend in the bottom panel is valid for both panels. The shifts for gold and silver are only shown for wavelengths longer than 600 nm and 400 nm, respectively, because the reflectivity drops below 90% at shorter wavelengths.