A method comprising: scanning a surface of a composite workpiece with multiple electromagnetic pulses emitted by a source, each of the multiple electromagnetic pulses being associated with a respective location on the surface of the composite workpiece; for each respective location on the surface of the composite workpiece: receiving a response to one of the multiple electromagnetic pulses at a multi-mode fiber, the response including multiple wavelength components; time shifting the multiple wavelength components with respect to each other by passing the response through the multi-mode fiber to produce a wavelength-binned pulse; sampling the wavelength-binned pulse at time intervals corresponding to the multiple wavelength components to determine a set of wavelength intensity levels corresponding to the multiple wavelength components; identifying a type or condition of material (222, 224, 226, 228) at the respective location on the surface of the composite workpiece based on the set of wavelength intensity levels; whereby the following steps are performed: spatially dispersing the multiple wavelength components using a diffraction grating system before time shifting the multiple wavelength components; focusing each of the multiple wavelength components into the multi-mode fiber using a lens; and synchronizing for each respective location a modulation period of the source of the electromagnetic pulse with a duration of the wavelength-binned pulse so that the wavelength components associated with a first electromagnetic pulse do not interfere with the wavelength component associated with a second electromagnetic pulse. scanning a surface of a composite workpiece with multiple electromagnetic pulses emitted by a source, each of the multiple electromagnetic pulses being associated with a respective location on the surface of the composite workpiece; for each respective location on the surface of the composite workpiece: receiving a response to one of the multiple electromagnetic pulses at a multi-mode fiber, the response including multiple wavelength components; time shifting the multiple wavelength components with respect to each other by passing the response through the multi-mode fiber to produce a wavelength-binned pulse; sampling the wavelength-binned pulse at time intervals corresponding to the multiple wavelength components to determine a set of wavelength intensity levels corresponding to the multiple wavelength components; identifying a type or condition of material (222, 224, 226, 228) at the respective location on the surface of the composite workpiece based on the set of wavelength intensity levels; whereby the following steps are performed: spatially dispersing the multiple wavelength components using a diffraction grating system before time shifting the multiple wavelength components; focusing each of the multiple wavelength components into the multi-mode fiber using a lens; and synchronizing for each respective location a modulation period of the source of the electromagnetic pulse with a duration of the wavelength-binned pulse so that the wavelength components associated with a first electromagnetic pulse do not interfere with the wavelength component associated with a second electromagnetic pulse. spatially dispersing the multiple wavelength components using a diffraction grating system before time shifting the multiple wavelength components; focusing each of the multiple wavelength components into the multi-mode fiber using a lens; and synchronizing for each respective location a modulation period of the source of the electromagnetic pulse with a duration of the wavelength-binned pulse so that the wavelength components associated with a first electromagnetic pulse do not interfere with the wavelength component associated with a second electromagnetic pulse.