Please wait a minute...

Frontiers of Mechanical Engineering

Front. Mech. Eng.    2019, Vol. 14 Issue (3) : 273-281
Progress in terahertz nondestructive testing: A review
Shuncong ZHONG()
Laboratory of Optics, Terahertz and Non-Destructive Testing, School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350116, China; School of Mechatronic Engineering and Automation, Shanghai University, Shanghai 200072, China
Download: PDF(2070 KB)   HTML
Export: BibTeX | EndNote | Reference Manager | ProCite | RefWorks

Terahertz (THz) waves, whose frequencies range between microwave and infrared, are part of the electromagnetic spectrum. A gap exists in THz literature because investigating THz waves is difficult due to the weak characteristics of the waves and the lack of suitable THz sources and detectors. Recently, THz nondestructive testing (NDT) technology has become an interesting topic. This review outlines several typical THz devices and systems and engineering applications of THz NDT techniques in composite materials, thermal barrier coatings, car paint films, marine protective coatings, and pharmaceutical tablet coatings. THz imaging has higher resolution but lower penetration than ultrasound imaging. This review presents the significance and advantages provided by the emerging THz NDT technique.

Keywords terahertz pulsed imaging (TPI)      nondestructive testing (NDT)      composite material      thermal barrier coating     
Corresponding Authors: Shuncong ZHONG   
Just Accepted Date: 19 April 2018   Online First Date: 21 May 2018    Issue Date: 24 July 2019
 Cite this article:   
Shuncong ZHONG. Progress in terahertz nondestructive testing: A review[J]. Front. Mech. Eng., 2019, 14(3): 273-281.
E-mail this article
E-mail Alert
Articles by authors
Shuncong ZHONG
Fig.1  Experimental setup of typical transmission THz pulsed spectroscopy (TPS) system [28]
Fig.2  Typical biased THz emitter [30]
Fig.3  Terahertz pulsed imaging (TPI) system [33]
Fig.4  Typical THz waveform measured from single-layer-coated structure [11]
Fig.5  Measured THz pulsed waveforms. (a) time-domain waveform [38]; (b) frequency amplitude spectra
Fig.6  THz NDT measurements of glass fiber composite material [39]. (a) Irregular fiber orientation (C-scan); (b) regular fiber orientation (C-scan); (c) C-scan of inclusion; (d) B-scan of inclusion; (e) C-scan of delamination; (f) B-scan of delamination
Fig.7  Fiber composite imaged by (a) THz and (b) ultrasound [40]
Fig.8  Thickness measurement of TBC topcoat using THz waves [41]. (a) Schematic diagram of the terahertz propagation path; (b) waveform of the terahertz wave measured
Fig.9  Comparison of averaged TGO thickness (SEM method) and delay time (THz method) [44]
Fig.10  TPI reflected waveform of multilayered car paint on carbon fiber substrate [48]. (a) B-scan map measured along the y-direction. (b) time-domain reflection waveform of a single pixel
Fig.11  Comparisons of SWT detail coefficients for intact and defected marine protective coatings [52]. A defect with radius of 12 mm and thickness of 0.18 mm was embedded inside (a) the three antifouling paint layers and (b) the anticorrosive paint layers
Fig.12  3D coating thickness images on two sides and center band of coated biconvex tablet [55]
1 E Brown, K McIntosh, K Nichols, et al. Photomixing up to 3.8 THz in low-temperature-grown GaAs. Applied Physics Letters, 1995, 66(3): 285–287
2 P Gu, M Tani, M Hyodo, et al. Generation of cw-terahertz radiation using a two-longitudinal-mode laser diode. Japanese Journal of Applied Physics, 1998, 37, Part 2(8B): L976–L978
3 J Smet, C Fonstad, Q Hu. Intrawell and interwell intersubband transitions in multiple quantum wells for far-infrared sources. Journal of Applied Physics, 1996, 79(12): 9305–9320
4 Y Jeong, B Lee, S Kim, et al. First lasing of the KAERI compact far-infrared free-electron laser driven by a magnetron-based microtron. Nuclear Instruments & Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, 2001, 475(1–3): 47–50
5 M Tonouchi. Cutting-edge terahertz technology. Nature Photonics, 2007, 1(2): 97–105
6 Y Shen, P Upadhya, E Linfield, et al. Terahertz generation from coherent optical phonons in a biased GaAs photoconductive emitter. Physical Review B: Condensed Matter and Materials Physics, 2004, 69(23): 235325
7 M Tani, K Horita, T Kinoshita, et al. Efficient electro-optic sampling detection of terahertz radiation via Cherenkov phase matching. Optics Express, 2011, 19(21): 19901–19906
8 C Yu, S Fan, Y Sun, et al. The potential of terahertz imaging for cancer diagnosis: A review of investigations to date. Quantitative Imaging in Medicine and Surgery, 2012, 2(1): 33–45
9 L Ho, R Müller, K C Gordon, et al. Terahertz pulsed imaging as an analytical tool for sustained-release tablet film coating. European Journal of Pharmaceutics and Biopharmaceutics, 2009, 71(1): 117–123
10 S Zhong, Y Shen, L Ho, et al. Non-destructive quantification of pharmaceutical tablet coatings using terahertz pulsed imaging and optical coherence tomography. Optics and Lasers in Engineering, 2011, 49(3): 361–365
11 Y Shen. Terahertz pulsed spectroscopy and imaging for pharmaceutical applications: A review. International Journal of Pharmaceutics, 2011, 417(1–2): 48–60
12 H Lin, Y Dong, D Markl, et al. Measurement of the intertablet coating uniformity of a pharmaceutical pan coating process with combined terahertz and optical coherence tomography in-line. Journal of Pharmaceutical Sciences, 2017, 106(4): 1075–1084
13 W Tu, S Zhong, Y Shen, et al. Nondestructive testing of marine protective coatings using terahertz waves with stationary wavelet transform. Ocean Engineering, 2016, 111: 582–592
14 K Su, Y Shen, J A Zeitler. Terahertz sensor for non-contact thickness and quality measurement of automobile paints of varying complexity. IEEE Transactions on Terahertz Science and Technology, 2014, 4(4): 432–439
15 J Dong, A Locquet, D S Citrin. Terahertz quantitative nondestructive evaluation of failure modes in polymer-coated steel. IEEE Journal of Selected Topics in Quantum Electronics, 2017, 23(4): 8400207
16 J Dong, J Bianca Jackson, M Melis, et al. Terahertz frequency-wavelet domain deconvolution for stratigraphic and subsurface investigation of art painting. Optics Express, 2016, 24(23): 26972–26985
17 Y Shen, T Lo, P F Taday, et al. Detection and identification of explosives using terahertz pulsed spectroscopic imaging. Applied Physics Letters, 2005, 86(24): 241116
18 J F Federici, B Schulkin, F Huang, et al. THz imaging and sensing for security applications—Explosives, weapons and drugs. Semiconductor Science and Technology, 2005, 20(7): S266–S280
19 R M Woodward, V P Wallace, D D Arnone, et al. Terahertz pulsed imaging of skin cancer in the time and frequency domain. Journal of Biological Physics, 2003, 29(2–3): 257–259
20 D Crawley, C Longbottom, V P Wallace, et al. Three-dimensional terahertz pulse imaging of dental tissue. Journal of Biomedical Optics, 2003, 8(2): 303–307
21 K Naito, Y Kagawa, S Utsuno, et al. Dielectric properties of eight-harness-stain fabric glass fiber reinforced polyimide matrix composite in the THz frequency range. NDT & E International, 2009, 42(5): 441–445
22 C Stoik, M Bohn, J Blackshire. Nondestructive evaluation of aircraft composites using reflective terahertz time domain spectroscopy. NDT & E International, 2010, 43(2): 106–115
23 P Lopato. Double-sided terahertz imaging of multilayered glass fiber-reinforced polymer. Applied Sciences, 2017, 7(7): 661–674
24 M Watanabe, S Kuroda, H Yamawaki, et al. Terahertz dielectric properties of plasma-sprayed thermal-barrier coatings. Surface and Coatings Technology, 2011, 205(19): 4620–4626
25 T Fukuchi, N Fuse, M Okada, et al. Topcoat thickness measurement of thermal barrier coating of gas turbine blade using terahertz wave. Electrical Engineering in Japan, 2014, 189(1): 1–8
26 D J Roth, L M Cosgriff, B Harder, et al. Self-calibrating terahertz technique for measuring coating thickness. Materials Evaluation, 2015, 73(9): 1205–1213
27 B Ferguson, X C Zhang. Materials for terahertz science and technology. Nature Materials, 2002, 1(1): 26–33
28 C J Strachan, T Rades, D A Newnham, et al. Using terahertz pulsed spectroscopy to study crystallinity of pharmaceutical materials. Chemical Physics Letters, 2004, 390(1–3): 20–24
29 R A Cheville, D Grischkowsky. Far-infrared terahertz time-domain spectroscopy of flames. Optics Letters, 1995, 20(15): 1646–1648
30 S Zhong, Y Shen, H Shen, et al. FDTD study of a novel terahertz emitter with electrical field enhancement using surface plasmon resonance. PIERS Online, 2010, 6(2): 153–156
31 H Yoneda, K Tokuyama, K Ueda, et al. High-power terahertz radiation emitter with a diamond photoconductive switch array. Applied Optics, 2001, 40(36): 6733–6736
32 X Ropagnol, R Morandotti, T Ozaki, et al. Toward high-power terahertz emitters using large aperture ZnSe photoconductive antennas. IEEE Photonics Journal, 2011, 3(2): 174–186
33 S Zhong, Y Shen, M Evans, et al. Quantification of thin-film coating thickness of pharmaceutical tablets using wavelet analysis of terahertz pulsed imaging data. In: Proceedings of 34th International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. Busan: IEEE, 2009
34 H Shen, L Gan, N Newman, et al. Spinning disk for compressive imaging. Optics Letters, 2012, 37(1): 46–48
35 H Shen, N Newman, L Gan, et al. Compressed terahertz imaging system using a spin disk. In: Proceedings of IEEE International Conference on Infrared, Millimetre, and Terahertz Waves (IRMMW-THz 2010). Rome: IEEE, 2010, 3–4
36 L Liu, Z Zhang, L Gan, et al. Terahertz Imaging with compressed sensing. In: Proceedings of IEEE 9th UK-Europe-China Workshop on Millimetre Waves and Terahertz Technologies (UCMMT 2016). Qingdao: IEEE, 2016, 50–53
37 I Amenabar, F Lopez, A Mendikute. In introductory review to THz non-destructive testing of composite material. Journal of Infrared, Millimeter, and Terahertz Waves, 2013, 34(2): 152–169
38 C D Stoik, M J Bohn, J L Blackshire. Nondestructive evaluation of aircraft composites using transmissive terahertz time domain spectroscopy. Optics Express, 2008, 16(21): 17039
39 T Chady, P Przemyslaw. Testing of glass-fiber reinforced composite materials using terahertz technique. International Journal of Applied Electromagnetics and Mechanics, 2010, 33(3–4): 1599–1605
40 A Anbarasu. Characterization of defects in fiber composites using terahertz imaging. Thesis for the Master’s Degree. Atlanta: Georgia Institute of Technology, 2008
41 T Fukuchi, T Ozeki, M Okada, et al. Nondestructive inspection of thermal barrier coating of gas turbine high temperature components. IEEJ Transactions on Electrical and Electronic Engineering, 2016, 11(4): 391–400
42 T Fukuchi, N Fuse, M Okada, et al. Topcoat thickness measurement of thermal barrier coating of gas turbine blade using terahertz wave. Electrical Engineering in Japan, 2014, 189(1): 1–8
43 T Fukuchi, N Fuse, M Okada, et al. Measurement of refractive index and thickness of topcoat of thermal barrier coating by reflection measurement of terahertz waves. Electronics and Communications in Japan, 2013, 96(12): 37–45
44 C Chen, D Lee, T Pollock, et al. Pulsed-terahertz reflectometry for health monitoring of ceramic thermal barrier coatings. Optics Express, 2010, 18(4): 3477–3486
45 T Yasui, T Yasuda, K Sawanaka, et al. Terahertz paintmeter for noncontact monitoring of thickness and drying progress in paint film. Applied Optics, 2005, 44(32): 6849–6856
46 Y Izutani, M Akagi, K Kitagishi. Measurements of paint thickness of automobiles by using THz time-domain spectroscopy. In: Proceedings of 37th International Conference on Infrared, Millimeter, and Terahertz Waves. Wollongong: IEEE, 2012
47 T Yasuda, T Iwata, T Araki, et al. Improvement of minimum paint film thickness for THz paint meters by multiple-regression analysis. Applied Optics, 2007, 46(30): 7518–7526
48 K Su, Y Shen, J A Zeitler. Terahertz sensor for non-contact thickness and quality measurement of automobile paints of varying complexity. IEEE Transactions on Terahertz Science and Technology, 2014, 4(4): 432–439
49 K Su, R K May, I S Gregory, et al. Terahertz sensor for non-contact thickness measurement of car paints. In: Proceedings of 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz). Mainz: IEEE, 2013
50 D J Cook, S J Sharpe, S Lee, et al. Terahertz time domain measurements of marine paint thickness. Optical Terahertz Science and Technology, 2007, TuB5
51 D J Cook, S Lee, S J Sharpe, et al. Accuracy and linearity of time-domain THz paint thickness measurements. SPIE Proceedings, Terahertz Technology and Applications, 2008, 6893: 68930H
52 W Tu, S Zhong, Y Shen, et al. Nondestructive testing of marine protective coatings using terahertz waves with stationary wavelet transform. Ocean Engineering, 2016, 111: 582–592
53 A J Fitzgerald, B E Cole, P F Taday. Nondestructive analysis of tablet coating thicknesses using terahertz pulsed imaging. Journal of Pharmaceutical Sciences, 2005, 94(1): 177–183
54 L Ho, R Müller, M Römer, et al. Analysis of sustained-release tablet film coats using terahertz pulsed imaging. Journal of Controlled Release, 2007, 119(3): 253–261
55 J A Zeitler, Y Shen, C Baker, et al. Analysis of coating structures and interfaces in solid oral dosage forms by three dimensional terahertz pulsed imaging. Journal of Pharmaceutical Sciences, 2007, 96(2): 330–340
56 V P Wallace, P F Taday, A J Fitzgerald, et al. Terahertz pulsed imaging and spectroscopy for biomedical and pharmaceutical applications. Faraday Discussions, 2004, 126: 255–263
57 L Ho, Y Cuppok, S Muschert, et al. Effects of film coating thickness and drug layer uniformity on in vitro drug release from sustained-release coated pellets: A case study using terahertz pulsed imaging. International Journal of Pharmaceutics, 2009, 382(1–2): 151–159
58 R K May, M J Evans, S Zhong, et al. Terahertz in-line sensor for direct coating thickness measurement of individual tablets during film coating in real-time. Journal of Pharmaceutical Sciences, 2011, 100(4): 1535–1544
Related articles from Frontiers Journals
[1] Kirsten BOBZIN, Lidong ZHAO, Thomas SCHLAEFER, Thomas WARDA. Preparation and characterization of nanocrystalline ZrO2-7%Y2O3 powders for thermal barrier coatings by high-energy ball milling[J]. Front Mech Eng, 2011, 6(2): 176-181.
[2] Yiliang ZHANG, Song YANG, Xuedong XU. Application of metal magnetic memory test in failure analysis and safety evaluation of vessels[J]. Front Mech Eng Chin, 2009, 4(1): 40-48.
[3] BAI Yue, GAO Qingjia, LI Haiwen, WU Yihui, XUAN Ming. Design of composite flywheel rotor[J]. Front. Mech. Eng., 2008, 3(3): 288-292.
Full text



  Shared   0