Fluorescent taggants with temporally coded signatures

In this paper, resonance energy transfer (RET) networks between chromophores are used to implement fluorescent taggants with temporally coded signatures. Because the temporal signature of such a fluorescent taggant is a phase-type distribution defined by the geometry of its RET network, the taggant design is not constrained by resolvable dyes and has a significantly larger coding capacity than spectrally or lifetime coded fluorescent taggants. Meanwhile, the detection process becomes highly efficient when the signatures are coded in the time domain. The taggant identification method is based on the multinomial distribution of detected photons and Maximum Likelihood Estimation, which guarantees high accuracy even with only a few hundred photons and also applies to a mixture of taggants in multiplex detection. Therefore, these temporally coded fluorescent taggants have great potential for both in situ and Lidar applications.