Application Of Terahertz Time Domain Spectroscopy In Rock Mineralogy

As a new detection technology,terahertz time-domain spectroscopy can be applied to many scientific fields because it can quickly and non-destructively perform the samples characterization and has a good ability to identify structurally similar substances.It has become the focus of research at present,but there are few applications researches on the field of petromineralogy.In the paper,the application potentials of terahertz time-domain spectroscopy have been explored on petromineralogy through using the characterizations of tourmaline,gabbro,and opal by the terahertz technology as innovation points.Its main contents and conclusions are as the following.(1)On the basis of previous optical parameter extraction models and methods,the data processing software and data consolidation comparison software are designed by the GUI graphical programming function in MATLAB software.This can greatly facilitate the processing of experimental data and reduce man-made data processing errors,which laid the foundation of the research on the applications of terahertz timedomain spectroscopy.(2)Terahertz time-domain spectroscopy are used as analyze anisotropic minerals in crystal structures.The characteristic absorption spectra test of tourmaline perpendicular to C-axis and parallel to C-axis in terahertz band were determined through selecting the Brazilian black tourmaline as the research object.The results present that tourmaline crystal modulation on terahertz pulse has a certain effect and can be used as a terahertz wave modulator or terahertz band polaroid.Tourmaline in THZ wave band has the same birefringence and dichroism and the birefringence is more distinct comparing with optical wavelengths.Terahertz time-domain spectroscopy has certain application potential in crystal orientation and identification of tourmaline and can be used as a tool of crystal mineral structure analysis.(3)The sensitivity of terahertz time-domain spectroscopy to trace elements in rock minerals has been investigated.The test sample is selected a section of angular flared gabbros of the Daochaohuo Taochao rock mass in the East Kunlun Mountains.The results show that the 1.4 THz terahertz wave is sensitive to the total iron contents of the samples and has a good correlation with it,which indicates the application of terahertz technology in composition analysis of the rock minerals is feasible.(4)The existence of water in water-bearing minerals has been identified and analyzed by terahertz time-domain spectroscopy.The opal rough are selected as test samples.The results show that the main forms of water in the opal stones are mainly gel water and a small amount of crystal water by testing the samples after heating treatment at different temperatures.The research shows that terahertz time-domain spectroscopy can be used as an effective supplementary means for the identification of opal stones,composition analysis,and determination of water content.Compared with traditional test methods,this technology has more obvious advantages on the measurement of molecular structure changes.