A pulse-assisted LSP broadband light source in flowing high-pressure liquid or supercritical fluid is disclosed. The light source includes a fluid containment structure for containing a high-pressure liquid or supercritical fluid. The light source includes a primary laser pump source and a high-repetition pulse-assisting laser light source. wherein the primary laser pump source is configured to direct a primary pump beam into a plasma-forming region of the fluid. The primary beam and the pulsed-assisting beam are configured to sustain a plasma within the plasma-forming region of the fluid within the fluid containment structure. A light collector element is configured to collect broadband light emitted from the plasma for use in downstream applications.