Laser plasmas interaction and spectral characteristics of plasma were investigated at a laser breakdown in a
normal atmosphere with the purpose of improving laser-induced breakdown spectroscopy sensitivity. Colliding plasmas
interaction was investigated depending on mechanism of absorption wave of laser radiation and distance between foci.
Laser supported detonation wave, breakdown wave and fast wave of ionization are absorption wave observed in
experiment. It was shown that seed electrons for cascade breakdown in front of fast wave of ionization is occurred due
to oxygen molecules photoionization. Molecular emission and collapse of intensity of plasma continuum during the
initial moments of laser plasma expansion were registered. The line/continuum ratio was essentially increased in case of
laser plasmas interaction. Thus laser plasmas interaction improves sensitivity of LIBS.
Mechanisms of absorption wave of laser radiation and spectral characteristics of laser plasma were investigated at a laser breakdown in a normal atmosphere. Q-switched Nd:YAG laser operated at 1064 and 532 nm were used in experiment. Laser pulse consisted of prepulse and basic pulse for both laser wavelengths. Time interval between pulses was 15 ns, time duration (FWHM) was 4 ns for 532 nm wavelength, 5 ns for 1064 nm wavelength. Molecular emission and collapse of intensity of plasma continuum during the initial moments of laser plasma expansion were registered. It was carried out examination of colliding plasmas interaction which depended on absorption wave mechanism and distance between focal points of lens. The magnification of integrated intensity in case of plasmas interaction is registered. Decay time of continuous spectrum and lines emission was increased thus contrast of emission lines was also increased.