Eiji Kato

Bio: Eiji Kato is an academic researcher from Advantest. The author has contributed to research in topics: Terahertz radiation & Iterative reconstruction. The author has an hindex of 3, co-authored 4 publications receiving 22 citations.

3D Imaging and analysis system using terahertz waves

Abstract: We have developed the “3D Imaging Analysis System” that uses terahertz waves, the world's first such system for practical applications. This system has an unprecedented capability for nondestructive three-dimensional spectroscopic analysis of the spatial distribution of constituents.

3D Spectroscopic computed tomography imaging using terahertz waves

Abstract: We have developed a three-dimensional spectroscopic imaging system that uses terahertz waves and is based on transmission computed tomography. Using this system, we demonstrate transmission three-dimensional computed tomography imaging of high refractive index objects, with identification of chemical components, by analyzing spectroscopic information.

Dynamic measurement of material properties using terahertz radiation with real-time thickness measurement for process control

Abstract: A method of determining material properties for an object under test is disclosed. The method comprises determining a thickness at a point on the object under test in a non-invasive manner. It also comprises obtaining a terahertz measurement by passing terahertz radiation through the object under test using a terahertz emitter and detecting the terahertz radiation using a terahertz detector. Finally, it comprises determining an optical property at the point on the object under test using a measurement value from the terahertz emitter and the terahertz detector and a measured value for the thickness at the point.

An investigation of petrochemical geological samples by terahertz pulse spectroscopy

Abstract: The analysis of petrochemical samples by Terahertz (THz) spectroscopy is investigated. THz spectroscopy is a nondestructive, contact-free analysis method for the study of many different materials. In this work, we show that the THz spectra can be used to get different chemical and structural information from a potential hydrocarbon source. Density of the geological samples has the potential for valuable information about the sample. For similar materials, refractive index is linearly proportional to density [1]. But, refractive index spectra lack the specificity that absorbance spectra have. Non-destructive absorbance maps are generated and are shown to be reproducible.

Review of Terahertz Tomography Techniques

Abstract: Terahertz and millimeter waves penetrate various dielectric materials, including plastics, ceramics, crystals, and concrete, allowing terahertz transmission and reflection images to be considered as a new imaging tool complementary to X-Ray or Infrared. Terahertz imaging is a well-established technique in various laboratory and industrial applications. However, these images are often two-dimensional. Three-dimensional, transmission-mode imaging is limited to thin samples, due to the absorption of the sample accumulated in the propagation direction. A tomographic imaging procedure can be used to acquire and to render three-dimensional images in the terahertz frequency range, as in the optical, infrared or X-ray regions of the electromagnetic spectrum. In this paper, after a brief introduction to two dimensional millimeter waves and terahertz imaging we establish the principles of tomography for Terahertz Computed tomography (CT), tomosynthesis (TS), synthetic aperture radar (SAR) and time-of-flight (TOF) terahertz tomography. For each technique, we present advantages, drawbacks and limitations for imaging the internal structure of an object.

Terahertz imaging based on optical coherence tomography [Invited]

Abstract: Three-dimensional (3D) terahertz (THz) imaging or THz tomography has recently proven to be useful for nondestructive testing of industrial materials and structures In place of previous imaging techniques such as THz pulsed/continuous-wave radar and THz computed tomography, we propose a THz optical coherence tomography using photonics- and electronics-based THz sources, and demonstrate thickness measurement and tomographic imaging in frequency regions from 400 to 800 GHz

Terahertz tomographic imaging of XVIIIth Dynasty Egyptian sealed pottery

Abstract: A monochromatic millimeter-wave imaging system coupled with an infrared temperature sensor has been used to investigate historic objects preserved at the Museum of Aquitaine (France). In particular, two-dimensional and three-dimensional analyses have been performed in order to reveal the internal structure of nearly 3500-year-old sealed Egyptian jars.

Terahertz Computed Tomography Using A Continuous-Wave Gas Laser

Abstract: A 3D continuous-wave (CW) terahertz computed tomography (CT) system employing a gas laser operating at 2.52 THz is presented. To shorten acquisition time on the premise of guaranteeing the image quality, the modified simultaneous algebraic reconstruction technique (MSART) coupled with image processing operations like the Gaussian low-pass filter (GLPF), open operation and close operation has been adopted in the paper. With the 2D results the 3D images of the samples have been also obtained. The reconstruction results illustrate the promising application prospects of this CW THz CT system.