Influence of component and structure on laser induced voltage in sandstone

Zhaohui Meng,Kun Zhao,Wenzheng Yue,Jing Zhu,Ru Chen,Shanzhe Zhang,Mengxi Chen,Honglei Zhan

doi:10.1063/1.5128200

Zhaohui Meng, Kun Zhao + Show 6 more

Open Access

https://doi.org/10.1063/1.5128200

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Abstract

In this paper, ultraviolet laser with the wavelength of 248 nm was employed to assess the laser-induced plasma transmission spectroscopy of four kinds of sandstone. The research focused on the interactions between the laser pulse and the component as well as the structure of sandstone. The more complex metal ion content the rock has, the larger voltage signal the sandstone shows with the same bias current applied. The metal ion can stimulate the formation of plasma excited by the laser. Meanwhile, the excited plasma moves faster in the sandstones with more pores and gives the rock a shorter rise time. The measured voltage effect in sandstone indicates that ultraviolet laser is an approach to identify lithology of stratum by the peak values and rising times.

Highlights

Laser pulses have been extensively used to study fundamental physical processes in solids
Component and structure information of the sandstone samples were examined with x-ray diffraction (XRD), infrared (IR) spectrometer, and scanning electron microscopy (SEM)
Based on the result of XRD, R, F, and Q1 were composed of quartz, calcite, and microcline; in contrast, Q2 consisted of quartz and dolomite (Fig. 1)

Summary

INTRODUCTION

Laser pulses have been extensively used to study fundamental physical processes in solids. The absorption of a photon in the visible or ultraviolet typically produces both electronic and vibration excitation in the surface and near-surface region of an irradiated solid (Ummadisingu et al, 2017; Liu et al, 2016). When the sample receives a nanoscale pulsed laser, the energy of photons of laser radiation in the very beginning of a pulse is transferred to the surface particle, an oscillating electric field is formed on the surface of the particle, the free conducting electrons in the particle collectively oscillate under the excitation of the oscillating electric field, the incident photon frequency is equal. The transport mechanism of plasma can be analyzed through the detected voltage spectra We call this method laser-induced plasma transmission spectroscopy (LIPTS). The relationships of peak of LIPTS signal (Vp), rise time and component, and the structure of the four sandstone samples were investigated

EXPERIMENTAL METHODS

AND DISCUSSION