One embodiment of the present invention provides a system that characterizes a biological sample by analyzing light emissions from the biological sample in response to an excitation. The system first radiates the biological sample with a laser impulse to cause the biological sample to produce a responsive light emission. Next, the system uses a wavelength splitting device to split the responsive light emission into a set of spectral bands of different central wavelengths. The system applies temporal delays to the set of spectral bands so that each spectral band arrives at an optical detector at a different time, thereby allowing the optical detector to temporally resolve the responsive light emission for each spectral band separately. Next, the system captures the delayed spectral bands within a single detection window of the optical detector. The system then processes the captured spectral bands.