Abstract: Apparatus and a related method for detecting laser pulses and classifying em in accordance with their wavelength, irradiance level, shape and time of occurrence. Each pulse received from a selected field of regard (10) is detected in a high-speed broadband radiometer (12), which generates a corresponding electrical pulse that is used to form a triggering pulse to control a gated camera (24) coupled to a transmission grating spectrometer (22). The gated camera (24) has an inherent delay time before it becomes active after receiving a gating signal (30). To compensate for this delay, light from each laser pulse passes through a fiber image delay line (16) before reaching the transmission grating spectrometer (22). Output data signals from the camera (24) are processed (40) to reduce the effects of background noise and converted (42) to a quantity indicative of wavelength.