Fig. 1. Microscale plume observation system

Fig. 2. Different laser ablation modes. (a) Transmission mode; (b) reflection mode

Fig. 3. Plumes of GAP under different nano-carbon powder concentrations and target thicknesses. (a) 0, d=109 μm; (b) 1%, d=107 μm; (c) 3%, d=107 μm

Fig. 4. Plumes of GAP under different infrared dye concentrations and target thicknesses. (a) 1%, d=138 μm; (b) 3%, d=148 μm; (c) 5%, d=134 μm; (d) 7%, d=155 μm

Fig. 5. Plumes of GAP under 3% nano-carbon powder concentration but different target thicknesses. (a) d=54 μm; (b) d=107 μm; (c) d=176 μm

Fig. 6. Plumes of GAP under 3% infrared dye concentration but different laser ablation modes. (a) Transmission mode; (b) reflection mode

Fig. 7. Propulsion performances under different laser ablation modes for two working conditions. (a) Momentum coupling coefficient; (b) specific impulse; (c) energy conversion efficiency