Theory for momentum transfer to a surface with a high-power laser

Abstract

A model is developed for the momentum transferred to a solid from a laser-supported gaseous detonation wave initiated in air above the surface. One-dimensional gasdynamic analysis is used for the detonation wave moving away from the surface and cylindrical blast-wave theory is employed to partially account for two dimensional effects. Momentum transfer coupling coefficients (impulse/laser energy) are calculated which are functions of the laser energy flux, pulse duration, and the beam and target surface areas. Results are compared with recent experimental data obtained using a high-power CO2 laser.

Photodestruction of human dental plaque bacteria: Enhancement of the photodynamic effect by photomechanical waves in an oral biofilm model

“…1). The PW were generated by the ablation of the target material [26] with a Q-switched ruby laser (Laser Applications, Inc., Orlando, FL) and launched into the reservoir containing the pL-c e6 conjugate solution. The operating parameters of the ruby laser were 694.3 nm, 2.1 J, and 23 nanoseconds pulse duration.…”

Intraocular measurements of pressure transients induced by excimer laser ablation of the cornea

“…In the high intensity regime (10 7 -10 8 W/cm 2 ), the ''variable energy blast wave'' theory allows quantitative estimation of the surface pressure time-history [20,21]. Assuming a fast vaporization and with reference to the irradiation conditions of this study, we can distinguish three distinct phases in the evolution of the pressure wave expanding outside the target in the air semi-space: (1) blast wave planar pumping while the laser is on, (2) planar decay, and (3) spherical decay.…”

An investigation of spatial distribution of laser ablation products and their deposition on a substrate in the case of laser action with sharp focusing

“…Therefore, modes of laser action of a long pulse duration (microseconds and longer) with sharp focusing of laser radiation onto the target may be of certain interest. Note that the processes of laser ablation under conditions of laser radiation with a high energy density acting on a target were studied to a sufficient detail both theoretically and experimentally [3,4]. In so doing, in the case of a fairly high intensity of laser radiation, a shock wave emerged in the ablation products, which propagated toward the radiation, and the shape of the plasma cloud reminded one of a highly extended ellipsoid with the absorption region located at its vertex [3][4][5].…”

“…Note that the processes of laser ablation under conditions of laser radiation with a high energy density acting on a target were studied to a sufficient detail both theoretically and experimentally [3,4]. In so doing, in the case of a fairly high intensity of laser radiation, a shock wave emerged in the ablation products, which propagated toward the radiation, and the shape of the plasma cloud reminded one of a highly extended ellipsoid with the absorption region located at its vertex [3][4][5]. The situation under consideration is characterized by the presence of sharp focusing of laser radiation, which presumes a rapid convergence of radiation after the lens to a very small spot.…”