Critical fluence effects in laser propulsion

摘要

The fluence dependence of the laser ablation of selected polymers was studied within the range from 1-150 J/cm~2. A TEA CO_2 laser operating at 10.6 μm with 300 ns main pulse length and up to 20 J pulse energy was used to ablate prepared polymer samples with single pulses of laser energy. Measurements of parameters such as the ablated mass per spot area (Δm_a), momentum coupling coefficient (C_m), specific impulse (I_(sp)), and internal efficiency (η_i) will be plotted as functions of fluence. Critical threshold effects observed throughout the experiments will be described in detail.