In order to avoid friendly fire incidents in the combat theater, novel covert identification systems and methods of identifying friendly forces are provided. The systems include at least a spectroscopic imaging device and a marker that interact with each other by using a synchronized, predetermined filter tuning sequence. The filter tuning sequence enables interacted photons to wavelength hop according to the predetermined tuning sequence. As a result, the covert identification system allows friendly forces to clearly identify each while avoiding detection by enemy forces that employ conventional broadband and night vision sensors.