Repeatability improvement in laser induced plasma emission of particle flow by aberration-diminished focusing

The influence of more concentrated energy distribution formed by an aspheric lens with eliminated spherical aberration on laser-induced air breakdown

“…result of plasma spectral uctuations is consistent with previous studies. 24 The inuence of spherical aberration on the plasma temperature and electron number density was investigated. The plasma temperature was calculated using the Boltzmann plot of the N ionic spectral lines at 399.50, 444.70, 460.15, 460.72, and 480.33 nm, and the electron density was calculated using the Ha 656.28 nm.…”

“…22 Compared with changing the laser mode, the condenser lens is more exible and operable, so it became the research highlight for optimizing laser focusing. [23][24][25] Zhang et al reported that they experimentally compared the effects of plano-convex lenses of different focal lengths on the air breakdown spectrum. 23 As the focal length decreased, the spectral intensity increased and the uctuation decreased.…”

“…22 Compared with changing the laser mode, the condenser lens is more flexible and operable, so it became the research highlight for optimizing laser focusing. 23–25…”

High spectral stability and quantitative accuracy of LIBS by optimization of a combined atomic and ionic line algorithm

“…For example, Hou et al 12 improved the LIBS signal quality by shaping the laser beam from a commonly used Gaussian profile to a flat-top profile. Yao et al 13 reported that aberration diminished focusing shrunk the laser focal region, leading to fewer plasma position fluctuations and higher signal repeatability. Yu et al reduced the spectral fluctuations using a gas mixture of helium (He), neon (Ne), and argon (Ar) as the surrounding ambiance.…”

An image auxiliary method for laser-induced breakdown spectroscopy analysis of coal particle flow

“…It is necessary to take measures to ensure the repeatability and stability of spectral data. Some researchers committed to reducing the probability of low quality laser breakdown by transforming and optimizing the LIBS experimental system, such as employing a conical tube, 22 dual lens, 23 short laser pulse width, 24 two-stage cyclone measurement system, 25 and other attempts. 26 However, although equipment optimization can improve the stability of measurement to a certain extent, it is still unable to avoid the generation of the invalid spectrum.…”