Apparatuses and methods for identifying and characterizing an impingement by electromagnetic radiation on a structure's surface. An array of input and output radiofrequency transmission lines are connected by photoconductive switches that conduct only when exposed to incident electromagnetic radiation. Each input line is assigned a unique input RF frequency. If a switch is exposed to radiation, the connection between the corresponding input and output lines closes, and an RF signal is output from the output port connected to the closed switch, while if the switch is not exposed to the incident radiation, the connection remains open and no RF signal is output. By analyzing the frequencies of the signals output at a port, the location of the radiation incident on the structure can be determined.