Effect of lens focusing distance on laser-induced silicon plasmas at different sample temperatures

Abstract

We investigated the dependence of laser-induced breakdown spectral intensity on the focusing position of a lens at different sample temperatures (room temperature to 300 °C) in atmosphere. A Q-switched Nd:YAG nanosecond pulsed laser with 1064 nm wavelength and 10 ns pulse width was used to ablate silicon to produce plasma. It was confirmed that the increase in the sample's initial temperature could improve spectral line intensity. In addition, when the distance from the target surface to the focal point increased, the intensity firstly rose, and then dropped. The trend of change with distance was more obvious at higher sample temperatures. By observing the distribution of the normalized ratio of Si atomic spectral line intensity and Si ionic spectral line intensity as functions of distance and temperature, the maximum value of normalized ratio appeared at the longer distance as the initial temperature was higher, while the maximum ratio appeared at the shorter distance as the sample temperature was lower.

Lens-to-sample distance effect on the quantitative analysis of steel by laser-induced breakdown spectroscopy

“…They pointed out that fs laser-produced plasma(LPP) expansion appears to be approximately two times faster than ns LPP expansion for the their experimental conditions. Until recent years, there also have many studies related to the laser focusing conditions effect on laser-induced plasma [19][20][21][22].…”

Role of Focusing Distance in Picosecond Laser-Induced Cu Plasma Spectra

“…When a femtosecond laser is used to ablate a copper target, the spectral intensity of Cu(I) and Zn(I) is higher when the laser is circularly polarized rather than linearly polarized [12]. The dependence of the spectral intensity of Si on the position of a lens, at different sample temperatures, is investigated by Zhang et al [13], while Guo et al analyzed the influence of the distance between the lens and the sample on spectral intensity and the vibrational temperature of the CN band, by using a nanosecond pulse to ablate polymethyl methacrylate [14]. Harilal et al investigated the spot size effects on propagation dynamics [15] and conversion efficiency [16] of laser-produced plasma in vacuum and argon atmosphere; the results show that the sharpening of plasma plume depends heavily on the spot size.…”

Effect of liquid aerosol temperature on the detection performance of LIBS for analysis of phosphorus element in water

“…These have been verified on a solid sample ( e.g. aluminum, aluminum alloy, steel, iron, slag, glass, silicon, soil, rock, gold, copper, brass, copper–zinc alloy, molybdenum–tungsten alloy, magnesium, germanium, titanium, inconel superalloys, nickel, tissue, and particles), 19,20,22,23,25–34,36,41–59 gas sample, 39 and liquid sample (water, molten metals, and molten salts) 60–65 by many researchers. For example, increasing the sample temperature results in a larger mass and volume of the laser ablation crater, stronger signal intensity and SNR, higher plasma temperature and electron density, and improved detection performance.…”

“…In addition, the sample temperature has a significant effect on the laser ablation crater (mass and volume) and rate, 18–23 signal intensity, 24 signal-to-noise ratio (SNR), 25 plasma properties (dynamic, morphology, temperature, and electron density), 18,21,26–33 experimental conditions (defocusing amount, laser energy, and delay time), 34–37 self-absorption, 38 and detection performance (repeatability, accuracy, and sensitivity) 27,39–42 of LIBS. These have been verified on a solid sample ( e.g.…”