Time-gated spectroscopic study of laser-ablation plume of biological tissue

We present for the first time, to our knowledge, the time-gated spectroscopy of laser ablation plume of biological tissue. Our experiment suggests that this spectroscopy is useful for detection of trace elements such as Ca, Na, K, etc. In comparison with the existing fluorescence diagnoses, Ca can be detected with much higher sensitivity, and any poisonous sensitizers like fluorescence dyes are not needed in our method. Accordingly, the time-gated spectroscopy of the laser-ablation plume is a promising candidate for optical biopsy in the near future. In laser-ablation of biological tissue, a Q-switched Nd:YAG laser is used as the light source, which supplies nearly 10 ns laser pulses at 1064, 532 and 266 nm with a repetition rate of 10 Hz.