Laser propulsion in a water environment is influenced by
oscillating features of a laser-induced bubble. In our study an optical beam
deflection method is used to investigate dynamics of laser-induced
semispherical cavitation bubbles near three different interfaces: the rigid
boundary (water-solid interface), the free surface (water-air interface)
and the liquid-liquid interface (water-soybean oil interface), and in the
bulk. The maximum radius of the first bubble oscillation Rmax1 was
widened and the collapse time T1 is prolonged in the
case of the rigid boundary. Rmax1 is diminished and T1 is shortened
in the case of the free surface and the water-oil interface, among which
the latter makes Rmax1 even smaller. In order to get the maximum
propelling force in different distances near different medium interfaces,
different pulse energy of the laser is used. The bubble moves toward the
rigid boundary and moves away from the free surface during its oscillations.
This will change the application point of the propelling force on the
object, and cause a change in the propelling direction of the object.