Conventional Optical Measurement Research Articles

AC susceptibility of magnetic markers in suspension for liquid phase immunoassay

AC susceptibility of magnetic markers in solution was studied for biosensor applications. First, frequency dependence of the susceptibility was measured, and size distribution of the markers was estimated by analyzing the experimental result with the so-called singular value decomposition (SVD) method. The size distribution estimated with the magnetic measurement agreed with that obtained from conventional optical measurement. Next, susceptibility measurement was applied to the liquid-phase immunoassay without bound/free (B/F) separation. We performed the detection of biotin-coated polymer beads in suspension using avidin-coated magnetic markers. Changes of the susceptibility and the size distribution caused by the binding reaction were shown.

Valence-EELS analysis of local electronic and optical properties of PMN–PT epitaxial film

This study investigated local electrical and optical properties of Pb(Mg 0.39Nb 0.61)–0.34 mol%PbTiO 3 solid solution (PMN–PT) film stacked on Si (0 0 1) wafer with (La,Sr)CoO 3− x /CeO 2/YSZ buffer layers. TEM-VEELS analysis of the PMN–PT thin film, which was grown epitaxially on the Si substrate with two coexisting phases of pseudocubic and tetragonal morphology, was firstly conducted using the TEM-VEELS method. The ELF has shown a bulk plasmon peak and two interband plasmon peaks. The interband transition has been interpreted in comparison with the joint density of state obtained from the measured dielectric function and the density of state calculated by the density functional theory. The interband transition from the O 2p band to Nb 4d/Ti 3d bands determines the optical properties around the band gap. The optical absorption of PMN–PT film has shown the band gap of 3.5 ± 0.2 V. The refractive index derived from the TEM-VEELS analysis in the nano-region of the film has agreed with that obtained with the conventional optical measurement from the macroscopic region.

M3-6 偏光した近接場光を用いたナノスケール温度・熱物性測定手法の開発(M3 熱流体デバイス)

Measurement of temperature distribution at nanoscale is absolutely important for the thermal design of high integrated devices. However, in conventional optical measurement techniques, the spatial resolution is limited by the diffraction limit of light, which is approximately half of the wavelength of the optical beam. Therefore, we have developed a novel optical nanoscale temperature measurement method using near-field microscope technique. We newly employed the polarization of light into the measurement principle, since the near-field polarization has a high sensitivity for the refraction index of the sample, which varies with temperature. In this method, highly polarization maintaining near-field optical fiber probe is necessary for increasing the measurement sensitivity. Hence, we have newly fabricated the single mode near-field optical fiber probe. In this paper, we report the verification of the new measurement principle and the comparison of the measurement sensitivity with the results using temperature dependence of reflectance.

INTERACTION OF ELECTRON AND NUCLEAR SPINS IN QUANTUM WELLS

We describe our resistively detected nuclear-spin relaxation measurements on bilayer electron systems in double quantum wells. The measurements were carried out to study the compressible-incompressible transition at total filling factor νtot = 1 and the canted antiferromagnetic order and its Goldstone mode predicted for νtot = 2. The data demonstrate how nuclear-spin relaxation can shed light on spin/pseudospin order and associated phase transitions that may not be visible through conventional transport or optical measurements.

Online Measurement Technique for Diameter Profile of Si Crystal in Growth Furnace of Czochralski Method

We have developed a new instrumentation technique for Si crystal growth process of Czochralski (CZ) method for the purpose of the productivity improvement. In this paper, we developed the online measurement technique for diameter profile of Si crystal in growth furnace. Our new technique can measure the crystal diameter profile with higher accuracy than conventional optical measurement. The features of this technique are the data correction method and the elimination method of the effect of crystal swing. The measurement error of maximum diameter is within 0.18mm, and the measurement error of minimum diameter is within 0.09mm. This technique contributes to the improvement of CZ Si crystal productivity.

LUMINESCENT AND TUNABLE 3D PHOTONIC CRYSTAL STRUCTURES

We report an investigation of luminescent and tunable photonic crystal structures formed by the infiltration and inversion of opal templates with high index and luminescent materials. Protocols are reported for the deposition of these materials and the properties of the resulting structures investigated by conventional structural and optical measurements. The properties of multi-layered and backfilled structures are reported and demonstrate the potential to modulate and statically tune the luminescence from photonic crystals.

A122 ナノスケール熱物性値計測のための近接場光サーモリフレクタンス信号の高感度検出(マイクロ・ナノスケール2)

In conventional optical measurement technique of thermophysical properties, the spatial resolution is limited by the diffraction limit of light, which is approximately half of the wavelength of the optical beam. Therefore, we have developed near-field optics thermal nanoscopy (NOTN), which is a thermal properties sensing technique (i.e. thermal conductivity and thermal diffusivity) using near-field light. This method has nanoscale spatial resolution (up to 10nm). Also, NOTN enables noncontact and in situ measurement of nanoscale devices and materials. In this paper, the detection of the near-field light with 100nm aperture fiber probe was demonstrated. Also, the evaluation of spatial resolution with 100nm aperture fiber probe was discussed.

Near-infrared intersubband absorption in InGaAs/AlAsSb grown by molecular beam epitaxy

We report here the molecular beam epitaxy growth and the intersubband absorption measurements of InGaAs/AlAsSb multi-quantum wells lattice matched to InP substrate. Polarization-resolved absorption spectra were measured either with a conventional optical absorption measurement system or a Fourier-transform infrared spectrometer. We have observed an intersubband transition at wavelength as short as 1.45 μm (0.855 eV) in 2.0 nm thick InGaAs/AlAsSb quantum wells. This is the shortest quantum well intersubband absorption wave length ever reported in any materials system.

Optical and electrical properties of semiconducting WS 2 thin films: From macroscopic to local probe measurements

Photosensitive WS 2 thin films are obtained by annealing in presence of a crystallization promoter like Ni or Co. Conventional optical and electrical measurements (conductivity, Hall effect, photoconductivity) are completed by various local probe investigations like scanning tunneling microscopy (STM) and conductive atomic force microscopy (AFM). This thorough study clarifies the respective role of the crystallites and the grain boundaries in the macroscopic measurements and gives information on the properties and on the photovoltaic prospect of the films. The optical properties of the thin films are comparable to those of WS 2 single crystals, with absorption excitonic peaks of same intensity at 1.94 and 2.36 eV. The films show a p-type behavior with a carrier concentration of p≅10 23 m −3 and a Hall mobility of μ H≅10×10 −4 m 2 V −1 s −1 at room temperature. The Hall mobility is thermally activated with an activation energy of 60–90 meV. The photoconductivity spectra show the first indirect transition at 1.35 eV and a decrease of the quantum efficiency at the excitonic-transitions energies. The transport in the film plane is mainly governed by the potential barriers at the grain boundaries. Using a conducting AFM, the crystallite edges are shown to be degenerate semiconductors, while STM current–voltage ( I–V) spectroscopy indicates that the flat WS 2 crystallites have a low density of surface states on the basal planes. Submicron solid-state junctions are fabricated on the film by depositing gold electrodes on single WS 2 crystallites (with an electrode surface of ∼0.2 μm 2). Under illumination the p-WS 2/Au micro-junctions show open circuit-voltages of up to 520 mV. The collection of photo-generated carriers is limited by recombination at the grain boundaries.

1.45 µm Intersubband Absorption in InGaAs/AlAsSb Grown by Molecular Beam Epitaxy

InGaAs/AlAsSb multi-quantum wells lattice matched to InP substrates have been grown by molecular beam epitaxy, and the intersubband transitions in doped quantum wells have been studied. By precisely controlling the As to Sb flux ratio and substrate temperature, fairly abrupt interfaces with 1–2 monolayers of compositionary varying layers in both heterointerfaces have been achieved as confirmed from the high-resolution transmission electron microscopy (HRTEM) lattice images. Polarization-resolved absorption spectra were measured either with a conventional optical absorption measurement system or a Fourier-transform infrared spectrometer. We have observed an intersubband transition as short as 1.45 µm (0.85 eV) in 2.0-nm-thick InGaAs/AlAsSb quantum wells. This is the shortest quantum well intersubband transition ever reported in any materials system.

Optical modeling of quantum wire arrays

Optical heterostructures composed of alternating three-dimensional dielectric layers are designed to have the same transmission and traversal time characteristics as quantum wire structures. In this manner, the time and transmission behavior of a quantum wire, very difficult to measure directly, can be determined from conventional optical measurements.

Characterization of precious opals: AFM and SEM observations, photonic band gap, and incorporation of CdS nano-particles

Gem-quality blue opals consisting of ≈ 200 nm silica spheres are synthesized and incorporated with CdS nanoparticles by a solution technique. The opals with and without CdS are characterized by atomic force microscopy, scanning electron microscopy and conventional optical spectroscopic measurements. The possibility of producing 3-dimensional arrays of nano-sized materials and photonic crystals is supported by these experiments.

Rheo-optical measurements on suspensions of magnetic recording particles (abstract)

New rheo-optic measurements of the orientation of magnetic particles (used in particulate recording media) in suspension under imposed external fields (hydrodynamic and/or magnetic) are presented. The apparatus consists of a rheo-optical device1 employing polarization modulation technology, and the external magnetic and flow field generating equipment (plane Poiseuille flow cell and quadrupole electromagnet). The polarization modulation dichroism measurement technique, which has the advantage of improved sensitivity and precision over conventional optical measurements, is able to characterize uniaxial single domain magnetic particle suspensions under external magnetic and hydrodynamic fields. Linear dichroism measurements, which reflect the degree of particle alignment about the field axis, are shown to be sensitive indicators of particle magnetic interactions, of effects of particle intrinsic magnetic properties, and of effects of particle shape. In this paper we focus on the comparison between effects of imposed magnetic and hydrodynamic fields on particle orientation for rodlike γ-Fe2O3, CrO2, and plate-like Ba ferrites. Relationships between the particle orientation due to the two external fields are established through dimensional analysis, and the ‘‘equivalent magnetic field,’’ which yields the same magnitude of dichroism obtained under a given flow field, is measured. The flow field and the equivalent magnetic field show a nearly linear relationship. Once the equivalent magnetic field plot is obtained experimentally, one can conveniently transform hydrodynamic field to applied magnetic field and then determine the particle orientation. Preliminary results indicate that this device represents the best technique for systematic investigation of magnetic particle orientation during simultaneous imposition of magnetic and hydrodynamic fields.

Glucose determination by a pulsed photoacoustic technique: an experimental study using a gelatin-based tissue phantom

A preliminary study of using a gelatin-based in vivo tissue model to investigate some of the near infrared photoacoustic characteristics that may influence the sensitivity of non-invasive photoacoustic detection of blood glucose in human tissue is described. It is shown that the optical absorption change due to glucose in the near infrared region is small and that the pulsed photoacoustic technique may offer a better detection sensitivity than other conventional optical transmission measurement systems being developed for blood glucose monitoring.

Properties of Alkali-Ion-Exchanged Glass Optical Waveguides. Optical Sensitivity of Monitoring Chemical Species at Surface

Abstract Glass optical waveguides (OWGs) doped with alkali ions were examined mainly in terms of optical sensitivity of monitoring surface chemical species located at surfaces. The maximum sensitivity (per 1 cm optical path length) for K+-doped glass OWGs was ca. 50 times as large as that of conventional optical measurements with normal incidence of monitoring light. Rb+-doped and Cs+-doped OWGs had higher sensitivities, but they showed rather large attenuation of the guided light.

Metrology package for electron beam exposure tool evaluation: Application to EBES4

Throughout the stages of electron beam (e-beam) exposure tool development and application, the machine performance needs to be accurately characterized. A series of tests have been developed and implemented to diagnose and optimize the AT&T in-house EBES4 system for both mask making and direct wafer writing. The techniques employed for these tests will be described, and the evaluation results and how they lend themselves to machine diagnostics will be illustrated for EBES4. The tests consist of a complement of optical inspection, scanning electron microscopy (SEM) imaging, MARKET analysis, and electrical probe metrology. Optical and SEM techniques served to examine the machine writing characteristics and exposure pattern quality. Partially developed images in positive resists accentuated errors due to improper exposure. Electrical probe metrology was used to quantify and optimize machine accuracy. Compared to conventional optical and SEM measurement techniques, electrical metrology offers the advantages of higher throughput, superior resolution and sensitivity, much better accuracy and precision, and abundant statistics. The standard manufacturing electron beam exposure system (MEBES) MARKET program was utilized to measure pattern misplacement due to intrafield and interfield distortions. The magnitude of stripe shear and butting errors was quantified by electrical linewidth measurement. The 256 μm stripe butting error on EBES4 has a mean value of 0.011 μm and 3 σ of 0.066 μm. Employing simple electrical testers such as box-in-box and bridge resistors, EBES4 demonstrated pattern placement precision of 0.069 and 0.066 μm, ‘‘‖mean‖+3σ,’’ in the x and y directions, respectively. Aligning globally to zero-level fiducial marks, machine level to level registration capability for direct writing was determined to be 0.093 and 0.110 μm, ‖mean‖+3σ, in the x and y directions, respectively. Again, with the aid of electrical testers, linewidth control across a 90 mm square writing area at 20 kV on EBES4 was measured to be 0.027 μm (3σ) for 0.375 μm isolated features. Such machine evaluation data can be used to prove-in system specifications, and can be fed back to both the machine designers and the users for system optimization and integrated circuits design rule development, respectively.

Absolute Cross Sections for Molecular Photoabsorption, Partial Photoionization, and Ionic Photofragmentation Processes

A compilation is provided of absolute total photoabsorption and partial-channel photoionization cross sections for the valence shells of selected molecules, including diatomics (H2, N2, O2, CO, NO) and triatomics (CO2, N2O), simple hydrides (H2O, NH3, CH4), hydrogen halides (HF, HCl, HBr, HI), sulfur compounds (H2S, CS2, OCS, SO2, SF6), and chlorine compounds (Cl2, CCl4). The partial-channel cross sections presented refer to production of the individual electronic states of molecular ions and also to production of parent and specific fragment ions, as functions of incident photon energy, typically from ∼20 to 100 eV. Total photoabsorption cross sections above the first ionization threshold are reported from conventional optical measurements obtained using line and continuum sources and from ‘‘equivalent-photon’’ dipole (e,e) electron scattering experiments. Partial photoionization cross sections for production of electronic states of molecular ions are obtained from photoelectron spectroscopy and from dipole (e,2e) coincidence measurements. Photoionization mass spectrometry and dipole (e, e+ion) coincidence studies provide measurements of partial cross sections for ionic photofragmentation (i.e., dissociative photoionization). Photoelectron anisotropy factors, which together with electronic partial cross sections provide cross sections differential in photon energy and in ejection angle, are also reported. There is generally good agreement between cross sections measured by the physically distinct optical and dipole electron-impact methods. The cross sections and anisotropy factors also compare favorably with selected ab initio and model potential (X-alpha) calculations which provide a basis for interpretation of the measurements.

Dynamics of molecular organization in agarose sulphate

AbstractNongelling solutions of structurally regular chain segments of agarose sulphate show disorder–order and order–disorder transitions (as monitored by the temperature dependence of optical rotation) that are closely similar to the conformational changes that accompany the sol–gel and gel–sol transitions of the unsegmented polymer. The transition midpoint temperature (Tm) for formation of the ordered structure on cooling is ∼25 K lower than Tm for melting. Salt‐induced conformational ordering, monitored by polarimetric stopped‐flow, occurs on a millisecond time scale, and follows the dynamics expected for the process 2 coil ⇌ helix. The equilibrium constant for helix growth (s) was calculated as a function of temperature from the calorimetric enthalpy change for helix formation (ΔHcal = −3.0 ± 0.3 kJ per mole of disaccharide pairs in the ordered state), measured by differential scanning calorimetry. The temperature dependence of the nucleation rate constant (knuc), calculated from the observed second‐order rate constant (kobs) by the relationship kobs = knuc(1 − 1/s) gave the following activation parameters for nucleation of the ordered structure of agarose sulphate (1 mg mL−1; 0.5M Me4NCl or KCl): ΔH* = 112 ± 5 kJ mol−1; ΔS* = 262 ± 20 J mol−1 K−1; ΔG*298 = 34 ± 6 kJ mol−1; (knuc)298 = (7.5 ± 0.5) × 106 dm3 mol−1 s−1. The endpoint of the fast relaxation process corresponds to the metastable optical rotation values observed on cooling from the fully disordered form. Subsequent slow relaxation to the true equilibrium values (i.e., coincident with those observed on heating from the fully ordered state) was monitored by conventional optical rotation measurements over several weeks and follows second‐order kinetics, with rate constants of (2.25 ± 0.07) × 10−4 and (3.10 ± 0.10) × 10−4 dm3 mol−1 s−1 at 293.7 and 296.2 K, respectively. This relaxation is attributed to the sequential aggregation processes helix + helix → dimer, helix + dimer → trimer, etc., with depletion of isolated helix driving the much faster coil–helix equilibrium to completion. Light‐scattering measurements above and below the temperature range of the conformational transitions indicate an average aggregate size of 2–3 helices.

Applications of laser Raman microprobe spectroscopy to the characterization of coals and cokes

Optical microscopy is widely used in the characterization of coals and cokes. This Paper shows that the laser Raman microprobe (MOLE) which combines an optical microscope and a Raman spectrometer can provide useful additional information. Three main areas were investigated: identification of minerals in coal and coke; structural characterization of coals and cokes; and the interaction of inorganic additives and coal. Where possible, the results were compared with conventional optical microscopy measurements whereby it was shown that the optical texture and Raman spectra of cokes are not closely related. The Raman spectra of high temperature cokes were used to estimate the size of microcrystalline regions.

Evaluation of Dosimetry Film by Neutron Activation and X-Ray Fluorescence

Photographic film was exposed to γ-rays from 226Ra and 60Co to levels of 5 mR to 5,000 R. Measurements of the Ag in the developed films by both (a) activation with neutrons from 252Cf and counting 110Ag (half life 24.4 sec) and (b) X-ray fluorescence correlated with the known exposures. In the lower ranges conventional optical density measurements were made, and the correlation with the activation and X-ray methods was good.