Ultra-broadband incoherent sources based on laser-sustained plasma

Abstract

Laser-sustained plasma (LSP) featured by intense radiation in the ultra-broadband spectral range from vacuum ultraviolet to mid infrared, has attracted general interest in high resolution imaging, spectroscopy, and precision inspection. As high power fiber lasers have advanced in recent years, LSP-based techniques for broadband incoherent sources have emerged. However, despite numerous research efforts over the decades, there is still a lack of a comprehensive review of the influence of both gas parameters and laser parameters on LSP and their underlying mechanism. In this review, we summarized the state-of-the-art research results based on LSP techniques. Starting from the physical processes of absorption and radiation, key characteristics of LSP have been analyzed by considering critical parameters including plasma density, laser absorption coefficient and radiation coefficient. Subsequently, the effect of laser parameters on LSP characteristics and the possible mechanism are analyzed in detail. Moreover, the optical diagnostics methodologies of these parameters are compared and evaluated. Essential applications of LSP technology as a light source, in material processing and laser propulsion are summarized. Finally, we discuss the existing problems, possible solutions and future research outlook of LSP technology.