Pulsed CO2 laser interaction with a metal surface at oblique incidence

Abstract
Thermal fluence deposition and surface pressure generation produced by a CO2 laser pulse (λ=10.6 μm, during 10 μs, maximum intensity 3 MW/cm2) have been measured as a function of angle of incidence ϑ on sheet aluminum in air. We find that air plasma ignition depends on the laser beam intensity I0 only, not on the surface‐normal flux I0 cosϑ. Conversely, the fluence deposition and surface pressure depend only on the product I0 cosϑ, and obey the square‐root and two‐thirds‐power dependences observed with simple I0 variation at normal incidence.