Simultaneous three-dimensional step-height measurement and high-resolution tomographic imaging with a spectral interferometric microscope

A noncontact, nonmechanical scanning, wide-field spectral interference microscope is developed for simultaneous measurement of three-dimensional step-height of discontinuous objects and tomographic imaging. A superluminescent diode (SLD) is used as a broadband light source and a liquid-crystal Fabry-Perot interferometer (LC-FPI) as a frequency-scanning device. By means of changing the injection current to the SLD, the spectral profile of the SLD is equalized, and a constant light input to the interferometer is achieved over the entire frequency-scan range. The Fourier-transform technique is used to determine both the amplitude and the phase of spectral fringe signals. Three-dimensional height distribution of a discontinuous object is obtained from the phase information, whereas optically sectioned images of the object are obtained either from the amplitude information alone or from the combination of both the amplitude and phase information. Experimental results with submicrometer resolution are presented for both step-height measurement and tomographic sectioning.     

Multilingual disaster information system: information delivery using graphic text for mobile phones

A multilingual disaster information system (MLDI) has been developed to overcome the language barrier during times of natural disaster. MLDI is a web-based system that includes templates in nine languages so that translated texts can be made available immediately. Mobile phone e-mail with graphic text is a useful tool for delivering multilingual disaster information. The visibility of graphic text on mobile phones was measured and found to be equivalent to the built-in font. However, visibility deteriorates as the character size becomes smaller, especially, on displays with poor resolution. This article also discusses the necessity of multilingual information and measures for a safe and barrier-free society.     

Selective and in-situ determination of carbonate and oxide particles in aqueous solution using laser-induced breakdown spectroscopy (LIBS) for wearable information equipment

Laser-induced breakdown spectroscopy (LIBS) has been applied for quantitative analysis of Al₂O₃, CaCO₃ and MgO particles suspended in water. In the single elemental system, the plasma emission intensities of Al, Ca and Mg were linearly increased with concentration of elements in the range of 1.0×10^?5–1.0×10^?3  M, 1.0×10^?4–2.0×10^?3 M and 8.0×10^?5 –4.0×10^?3 M, respectively. We also investigated the concentration dependence of breakdown spectra for suspended mixtures of Al₂O₃, CaCO₃ and MgO particles. The emission lines, such as Al I, Ca I, Ca II and Mg I, were appeared in the LIBS spectrum simultaneously, and each emission peak could be deconvoluted. The plasma emission intensities of Al, Ca and Mg in the multielemental system were also linearly increased with their concentrations in the range of 1.0×10^?5–1.0×10^?3 M, 1.0×10^?4–2.0×10^?3 M and 4.0×10^?4–2.0×10^?3 M, respectively. LIBS was found to be available for quantitative and qualitative measurement of the concentrations of Al₂O₃, CaCO₃ and MgO particles suspended in water. The present results suggest that LIBS is a potentially useful tool for in-situ analysis on particles composition and concentrations for environmental monitoring by the wearable information equipments.     

Illumination control system for adaptive dynamic range control

Abstract— We have developed an illumination control system for adaptive dynamic range control. This system satisfies several performance requirements for image quality and reliability. A projection system using the illumination control system can reproduce images with optimum brightness for each image.     

Static capacitance contrast of LSI covered with an insulator film in low accelerating voltage scanning electron microscope

A new image contrast is reported for LSIs covered with an insulator film in a low accelerating voltage scanning electron microscope. The surface region above the conducting lines is often observed brighter than that without conducting lines. This contrast is quasi-stationarily observed contrary to well-known capacitive-coupled voltage contrast, and is called static capacitance contrast. The optimum irradiation conditions for the maximum image contrast is studied and its mechanism is discussed.     

Transmission line tower models in frequency domain

This paper proposes a transmission line tower model in frequency domain for back-flashover analysis, which has a uniform characteristic impedance and a uniform propagation constant. Most conventional tower models are constructed as a constant and uniform parameter transmission line that is independent of frequency. However, the authors' models have the frequency dependency of the characteristic impedance and the propagation constant to express the frequency characteristic of the transmission line tower. Two models, a cylinder model and a four-frames model, were investigated to simulate the tower. Their surge responses were computed by numerical electromagnetic field analysis based on the moment method. From the results, the two-port circuit constants were calculated in the frequency domain, and the characteristic impedance and the propagation constant are derived from them. The complex artificial oscillations appeared in frequency dependency of the parameters because the parameters were calculated numerically. The equations with analytical form were obtained by approximating with a smooth curve to the oscillations. It is possible for the equations to represent the transmission line constants as a function of geometrical parameters such as the tower height and the radius. Close agreement was found between the surge response computed by the numerical electromagnetic field analysis and the result calculated by inverse Laplace transformation of the analytical equations. To prove the model, the experimental results were compared with the computed ones of the cylinder model that has arms, and it was shown that the new model agrees closer with the experiment than conventional transmission line models.     

Spectral interference Mirau microscope with an acousto-optic tunable filter for three-dimensional surface profilometry

A nonmechanical scanning Mirau-type spectral interference microscope has been developed for the measurement of three-dimensional surface profiles of discontinuous objects. An acousto-optic tunable filter (AOTF) is used as a high-resolution spectral filter, which scans the optical frequency of the broadband light emitted from a superluminescent diode. To generate spectral fringes that make full use of the limited coherence length of the filtered light we unbalanced the Mirau interferometric system by positioning the reference mirror nearly halfway between the top and the bottom of the step height. When the frequency of the broadband light source is scanned by an AOTF, the interference fringes move in opposite directions on the top and the bottom of the object. To uniquely determine the sign of the fringe movement over the large area of the object, we developed a three-dimensional Fourier-transform technique, and from the detected sign of the fringe movement and phase information, we determined the three-dimensional step height. Experimental results of the measurement of 100-microm step height are presented. The main advantages of the proposed system are that it provides nonmechanical scanning and a large measurement range without ambiguity in the sign of the phase.     

Microwave-assisted steam distillation for simple determination of polychlorinated biphenyls and organochlorine pesticides in sediments

A novel sample extraction technique for polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) analysis using microwave-heating device is developed. In this study, microwave-assisted extraction (MAE) and steam distillation techniques were combined. Desorption of the anatytes from solid matrixes was accelerated with water vapor which was generated by microwave irradiation. A sample holder in a commercial microwave extraction cell kept the sample from direct contact with the organic solvent for analytes trapping during the treatment process. Therefore, relatively clean extracts were obtained with small amount of solvents. Without any cleanup steps, the obtained extract could be analyzed with gas chromatograph/mass spectrometers (GC/MS). Six PCB congeners (PCB15, 28, 70, 101, 180, 194, 209) and three OCPs (gamma-HCH, 4,4'-DDE, 4,4'-DDD) in two marine sediment samples (a sediment collected from a bay of Kyusyu Island, Japan, and a certified reference material NIST SRM1944) were analyzed by using this microwave-assisted steam distillation (MASD) technique and another extraction method (exhaustive steam distillation, MAE, and Soxhlet extraction); and comparisons of the results are shown in this report. Although recovery yields of highly chlorinated biphenyls (PCB180, 194, 209) and relatively polar OCPs (gamma-HCH, 4,4'-DDD) were low (30-60%) compared with other analytes (PCB15, 28, 70, 101, 4,4'-DDE; recovery, 80-100%), use of isotope labeled internal standards for the MASD technique gave comparable results with the values obtained by other extraction methods and the certified values in the samples.     

Microassembly of semiconductor three-dimensional photonic crystals

Electronic devices and their highly integrated components formed from semiconductor crystals contain complex three-dimensional (3D) arrangements of elements and wiring. Photonic crystals, being analogous to semiconductor crystals, are expected to require a 3D structure to form successful optoelectronic devices. Here, we report a novel fabrication technology for a semiconductor 3D photonic crystal by uniting integrated circuit processing technology with micromanipulation. Four- to twenty-layered (five periods) crystals, including one with a controlled defect, for infrared wavelengths of 3-4.5 microm, were integrated at predetermined positions on a chip (structural error <50 nm). Numerical calculations revealed that a transmission peak observed at the upper frequency edge of the bandgap originated from the excitation of a resonant guided mode in the defective layers. Despite their importance, detailed discussions on the defective modes of 3D photonic crystals for such short wavelengths have not been reported before. This technology offers great potential for the production of optical wavelength photonic crystal devices.