Absorption-Enhanced Liquid Ablatants for Propulsion with TEA CO2 Laser

A technique based on measuring force as a function of time on laser-ablated targets was applied to the study of water solutions of Sodium Tetrafluoroborate [NaBF4], a compound that strongly absorbs radiation in the 8-11 mm wavelength interval. A TEA CO2 laser of wavelength 10.6 gm, 300 us pulsewidth and 8 J pulse energy, was used for ablation of water diluted NaBF4 contained in a conical aluminum nozzle. Net imparted impulse and coupling coefficient were derived from the force sensor data and are reported below.