Patent ID: 8125627
Filing Date: 2012-02-28
Classification: G01J,G01N

Abstract:
1. A laser induced plasma spectroscopy system for detecting trace elements on a surface of a target at a stand-off distances of at least 20 meters, comprising: a first YAG laser having a frequency-shifted, pulsed beam having a wavelength of 266 nanometers; a second laser having a pulsed beam, the pulsed beam of the second laser having a peak energy, a wavelength, a pulse width at half maximum, and a spot diameter at the target; at least one telescopic focusing optics for focusing of the pulsed beam of the first YAG laser on the surface of the target, wherein the pulsed beam of the first YAG laser is optically coupled to the at least one telescopic optics, such that the beam of the first YAG laser induces a plasma on the surface of the target at the stand-off distance, when the pulsed beam of the first YAG laser is triggered, and the second laser is optically aligned and the pulsed beam of the second laser has the peak energy, the wavelength, the pulse width at half maximum, the wavelength and the spot diameter selected such that the pulsed beam of the second laser stimulates amplified emissions from the plasma generated by the beam of the first YAG laser; a spectroscope for detecting the amplified emissions; and a time-delay controller for triggering the emission of the pulsed beam of the first YAG laser and controlling the emission of the pulsed beam of the second laser, wherein a delay between triggering of the pulsed beam of the first YAG laser and the emission of the pulsed beam of the second laser is no greater than twelve microseconds, and the time-delay controller activates the spectroscope such that the amplified emissions are detected by the spectroscope, and the pulsed beam of the second laser has the peak energy, the wavelength, the pulse width at half maximum, the wavelength and the spot diameter selected such that the peak intensity of a plurality of peaks in the amplified emissions spectra that are detected by the spectroscope at the stand-off distance are at least three times the intensity of the same peaks if the plasma induced by the first YAG laser is not amplified by the second laser.