Stochastic resonance-enhanced laser-based particle detector

This paper presents a Laser-based particle detector whose response was enhanced by modulating the Laser diode with a white-noise generator. A Laser sheet was generated to cast a of the object on a 200 dots per inch, 512 times 1 pixels linear sensor array. The Laser diode was modulated with a white-noise generator to achieve stochastic resonance. The white-noise generator essentially amplified the wide-bandwidth (several hundred MHz) noise produced by a reverse-biased Zener diode operating in junction-breakdown mode. The gain in the amplifier in the white-noise generator was set such that the Receiver Operating Characteristics plot provided the best discriminability. A monofiber 40 AWG (~80 mum) wire was detected with ~88% True Positive rate and ~19% False Positive rate in presence of white-noise modulation and with ~71% True Positive rate and ~15% False Positive rate in absence of white-noise modulation.