Nanophotonic crystals have multiple applications that support detection, communications, and display technologies. Their influence, which originates in their orientation and index of refraction, shows tunable selectivity of the distribution of light by emission angle and wavelength. Wavelength- and angle-resolved cathodoluminescence (WARCL) is a very powerful technique that reveals the distribution of light by wavelength and angle (or the energy and momentum bases, respectively) in relation to the electron beam excitation position.