[Effect of carbon coating on radiation intensity of laser-induced metal plasmas]

In order to reduce the reflectance of laser beam on sample surface and enhance the radiation intensities of laser-induced metal plasma, a means has been studied for carbon coating on the surface of steel sample. The experimental results showed that the line intensities of the laser plasma formed when a high-energy neodymium glass laser (approximately 25 J) was used to generate the plasma in air at atmospheric pressure increased by a factor in the range of 10%-28% for the steel sample with the carbon coating. The excitation temperature of laser plasma was measured to explain the mechanism that the line intensities increase. In addition, it was found that the stronger intensity of atomic emission spectrum appeared at the radial location 1 mm in the laser plasma, not at the central place.