A review of the LIBS analysis for the plasma-facing components diagnostics

•PFCs are crucial parts of the fusion machines and LIBS is a robust methodology for its study due to its unique merits.•The investigation of impurities, anti-corrosion materials, and the diagnostics of fuel retention on the PFCs is presented.•Conventional, back-collection, and dual pulse LIBS methods, their merits and requirement for fusion research are explained.•Identification of elements and molecular band, spatial and depth profile and hardness analysis by LIBS are discussed. Fusion energy has great potential over other sources of energies due to the abundance of fusion fuel on the Earth and tokamak has turns out to be the best technique to harvest fusion energy. However, a continuous operation of a tokamak involves challenges due to plasma-wall interaction, e.g. erosion, re-deposition, fuel retention, and impurities control. For an efficient operation, the tokamak wall has to be remotely monitored and laser-induced breakdown spectroscopy (LIBS) seems to be the most suitable technique for this purpose. Multiple LIBS techniques (e.g. back-collection, VUV LIBS, DP-LIBS) for this purpose are reviewed in this contribution. The role of pressure, excitation wavelength and atmospheric effect has also been discussed. LIBS studies of spatial and depth profiles of W, Be, Al, Mo, Li, C based materials with impurities are presented as well and compared to other analytical methods. At last, the measurement of layer-wise matrix hardness is also discussed.