High-energy pulsed CO2-laser-target interactions in air

Abstract

Observations of the interaction of high-energy CO2 laser radiation with different target materials in air are reported. The plasma initiated on carbon and aluminum targets was observed with high-speed streak and framing cameras and electrostatic probes. The threshold for maintenance of radiation-driven absorption waves was found to be about 4×107 W/cm2 for a focal spot radius of 0.2–0.3 cm. The total impulse delivered to targets of various sizes and materials was measured along with simultaneous measurement of total energy and the power of the laser pulse. The impulse data were correlated with a simple cylindrical shock-wave model, which predicts that the impulse scales as the target area and as the square root of the focal spot area.