Highly focused supersonic microjets

TL;DR

This paper presents a method to produce highly focused, high-velocity microjets using laser-induced vaporization in capillaries, with potential applications in needle-free drug delivery.

Contribution

It introduces a novel laser-based technique for generating controlled, high-speed microjets with high reproducibility and proposes a semi-empirical model for velocity prediction.

Findings

Jet velocities up to 850 m/s achieved

High reproducibility and controllability demonstrated

Semi-empirical relation for jet velocity developed

Abstract

The paper describes the production of thin, focused microjets with velocities up to 850 m/s by the rapid vaporization of a small mass of liquid in an open liquid-filled capillary. The vaporization is caused by the absorption of a low-energy laser pulse. A likely explanation of the observed phenomenon is based on the impingement of the shock wave caused by the nearly-instantaneous vaporization on the free surface of the liquid. An experimental study of the dependence of the jet velocity on several parameters is conducted, and a semi-empirical relation for its prediction is developed. The coherence of the jets, their high velocity and good reproducibility and controllability are unique features of the system described. A possible application is to the development of needle-free drug injection systems which are of great importance for global health care.