Nondestructive characterization of nanoporous alumina films using terahertz scattering imaging

Acoustic microscopy characterization of highly-ordered anodized nanoporous alumina films for nanotechnology applications

“…THz reflectivity experiments provide nondestructive verification of the film thicknesses. Previous THz measurements [16,17] also indicate significant nonuniformity in portions of the films.…”

“…In general, the birefringence of porous materials is related to the crystal structure, lattice arrangement, and structural parameters, such as porosity [21] and pore size [45]. We refer the reader to [16,17] for the detailed discussion on birefringence as well as the regularity of the surface morphology of the NP Al 2 O 3 films.…”

“…Despite numerous investigations on characterizing NP materials, most only focus on optical techniques. Of interest to the current work are earlier studies [16,17] in which the homogeneity and anisotropy of NP Al 2 O 3 films on Al substrates were characterized nondestructively by terahertz (THz) imaging and THz spectroscopy. The observed rough surface morphology and anisotropy based on the THz results were validated by crosssectional field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and xray diffraction (XRD).…”

Applications of THz Spectral Imaging in the Detection of Agricultural Products

“…THz spectral imaging can be used for 3D imaging of a sample and analysis of its chemical composition by extracting its optical parameters in the THz region [18]. At present, THz spectral imaging is used in many fields, such as aerospace [19][20][21], biomedical [22][23][24], security detection [25][26][27], material performance analysis [28][29][30], and food quality [31][32][33]. In this paper, the application of THz spectral imaging in agriculture is reviewed, and the challenges and prospects of THz spectral imaging techniques are discussed.…”