Femtosecond fiber-laser-based laser-induced breakdown spectroscopy

This paper reports the LIBS studies on elemental composition detection and identification by employing a femtosecond (fs) fiber laser. High quality LIBS spectra were obtained in air using near-infrared fs fiber laser coupled with a broadband high sensitivity spectrometer without gating control. Specific ion and neutral emission lines of different materials have been characterized by line scanning, including metals, glasses and even explosive materials. Different laser parameters including pulse energy, repetition rate, scanning speed and integration times have been investigated to optimize the sensitivity. Results show that faster scanning speed and higher pulse energies can greatly enhance the signal level and reduce the integration time. The LIBS spectra are highly reproducible at different repetition rates up to 1 MHz. Furthermore, detection of explosive materials was also achieved and both the constituent elemental emission and the CN and C2 molecules emission were collected. Compared with conventional LIBS, fs fiber laser based LIBS system have advantages of less sample heating and damage, better spatial resolution and signal to background ratio, compact, reliable and cost-effective. This shows a potential portable LIBS system for versatile and rapid analysis of chemical and special explosive materials.