Intense underwater laser propagation, ionization and heating for remote shaped plasma generation

Intense underwater laser propagation, filamentation, and ionization are being investigated at NRL for many Navy applications, including remote undersea laser acoustic generation for low-frequency long-range sonar, as well as advanced micromachining using underwater laser-guided discharges. The key to low-frequency laser acoustic generation is shaping of the heated underwater volume, with more elongated volumes producing longer-duration acoustic pulses with more energy at low-frequencies.