Color ellipsoscope for real-time imaging of nanometer-scale surface phenomena

An imaging method was developed based on null ellipsometry with a white-light source. It is useful for visualizing the kinetics of fast surface phenomena on the nanometer scale.     

Welfare of calves - 2. Increase in vertebral artery blood flow following exsanguination by neck sticking and evaluation of chest sticking as an alternative slaughter method

The role of the vertebral arteries in delaying loss of sensibility following neck sticking in slaughter calves was investigated. Vertebral artery blood flow was measured using probes before, during and after electrical stunning and slaughter. Systemic blood pressure, electrocorticogram, visually evoked responses and the occurrence of carotid occlusions were also recorded. When carotid occlusion occurred, the time to onset of brain failure was delayed based on the development of an isoelectric state. In addition, when carotid occlusion occurred the mean arterial blood pressure was sustained for longer following slaughter, and concurrently vertebral artery blood flow could be maintained at about 30% of its initial level for up to 3 min. In some animals vertebral artery flow increased substantially following sticking. When chest sticking was used no occlusion of vessels occurred, mean arterial blood pressure fell promptly (within 8 s) and the onset of an isoelectric state did not extend beyond one minute. In addition, visually evoked responses were not present after 5 s following chest sticking.     

Linearized method: A new approach for kinetic analysis of central dopamine D(2) receptor specific binding

We proposed a new method (;linearized method') to analyze neuroleptic ligand-receptor specific binding in a human brain using positron emission tomography (PET). We derived the linear equation to solve four rate constants, k(3), k(4), k(5), k(6) from PET data. This method does not demand a radioactivity curve in plasma as an input function to the brain, and can perform fast calculations in order to determine rate constants. We also tested the nonlinearized method including nonlinear equations which is a conventional analysis using plasma radioactivity corrected for ligand metabolites as an input function. We applied these methods to evaluate dopamine D(2) receptor specific binding of [(11)C] YM-09151-2. The value of B(max)/K(d)=k(3)/k (4) obtained by the linearized method was 5.72+/-3.1 which was consistent with the value of 5.78+/-3.4 obtained by the nonlinearized method.     

Quantitative analysis of metabolic gases by multichannel Raman spectroscopy: use of a newly designed elliptic-spherical integration type of cell holder

We describe the quantitative analysis of some metabolic gases bymultichannel Raman spectroscopy. Raman spectra were measured forair, acetone, ammonia, carbon dioxide, and mixed gas consisting ofacetone, ammonia, and air. We designed a new elliptic-sphericalintegration type of cell holder to obtain the Raman spectra of gaseswith a high signal-to-noise ratio. Concentrations of acetone, ammonia, and carbon dioxide were determined by the peak intensities ofRaman bands at 2940, 3228, and 1385 cm(-1), respectively. To compensate for the fluctuations of Ramanintensities caused by several factors, such as the fluctuations oflaser power, the peak intensity of a band at 2324 cm(-1) dueto nitrogen gas was used as an internal intensity standard. Thecorrelation coefficient between the corrected Raman intensity at 2940cm(-1) and the concentration of acetone was calculated to be0.984 for a concentration range of 2-12 ppm. The detection limitof acetone gas was found to be 2 ppm.     

Fluid jet polishing of optical surfaces

We present a new finishing process that is capable of locally shaping and polishing optical surfaces of complex shapes. A fluid jet system is used to guide a premixed slurry at pressures less than 6 bars to the optical surface. We used a slurry comprising water and 10% #800 SiC abrasives (21.8 mum) to reduce the surface roughness of a BK7 sample from 350 to 25 nm rms and to vary the shape of a polished sample BK7, maintaining its surface roughness of 1.6 nm rms, thereby proving both the shaping and polishing possibilities of the presented method.     

Laser-speckle angular-displacement sensor: theoretical and experimental study

A novel, to our knowledge, method for the measurement of angular displacement for arbitrarily shaped objects is presented in which the angular displacement is perpendicular to the optical axis. The method is based on Fourier-transforming the scattered field from a single laser beam that illuminates the target. The angular distribution of the light field at the target is linearly mapped on a linear image sensor placed in the Fourier plane. Measuring this displacement facilitates the determination of the angular displacement of the target. It is demonstrated both theoretically and experimentally that the angular-displacement sensor is insensitive to object shape and target distance if the linear image sensor is placed in the Fourier plane. A straightforward procedure for positioning the image sensor in the Fourier plane is presented. Any transverse or longitudinal movement of the target will give rise to partial speckle decorrelation, but it will not affect the angular measurement. Furthermore, any change in the illuminating wavelength will not affect the angular measurements. Theoretically and experimentally it is shown that the method has a resolution of 0.3 mdeg ( approximately 5 murad) for small angular displacements, and methods for further improvement in resolution is discussed. No special surface treatment is required for surfaces giving rise to fully developed speckle. The effect of partially developed speckle is considered both theoretically and experimentally.     

Efficient Nd:YAG Laser Frequency Doubling with Periodically Poled KTP

Periodically poled flux-grown KTiOPO(4) was used for efficient extracavity 1064-nm Nd:YAG laser frequency doubling. A conversion efficiency exceeding 65% was obtained in Q-switched operation, and 1.34 W of average frequency-doubled power was generated with 2.2 W of mode-locked laser output. The conversion efficiency is approximately two times higher for periodically poled KTP than for conventional type II phase-matched KTP. The measurements indicate that periodically poled KTP is less susceptible to optical damage than type II KTP.     

Linearity of the Faraday-rotation-type ac magnetic-field sensor with a ferrimagnetic or ferromagnetic rotator film

We analyze the linearity and modulation depth of ac magnetic-field sensors or current sensors, using a ferrimagnetic or ferromagnetic film as the Faraday rotator and employing the detection of only the zeroth-order optical diffraction component from the rotator. It is theoretically shown that for this class of sensor the condition of a constant modulation depth and that of a constant ratio error give an identical series of curves for the relationship between Faraday rotation angle Θ and polarizer/analyzer relative angle Φ. We give some numerical examples to demonstrate the usefulness of the result with reference to a rare-earth iron garnet film as the rotator.     

Simulations of time series of atmospherically distorted wave fronts

A comparatively simple way to generate time series of atmospherically distorted wave fronts is described and tested. Temporal power spectra of Zernike aberrations, extracted from the time series, agree very well with theoretical predictions. A method for generation of longer time series is also shown to give results in accordance with theory, except for the lowest temporal frequencies modeled. A way to superimpose several time series of wave fronts to generate a multilayer model of the atmosphere is briefly discussed.     

Polarization-dependent photothermal beam deflection for the determination of the order parameter C(2) in a laser-oriented polymer system

We demonstrate polarization-dependent photothermal beam deflection as a powerful tool for analyzing quasi-two-dimensional molecular orientation. As examples we used two laser-beam-oriented polymer systems: DR1 in poly(methyl methacrylate) (PMMA) and PMMA with covalently bound DR1 and for comparison Phenol Blue in PMMA. Different order parameters C(2), for these systems have been found. It was also possible to orient by laser beam the DR1 chromophores cyclically by changing the polarization direction of the orienting laser beam and following these chromophore reorientations. The long-term stability of the orientation was investigated as well. The irreversible bleaching that is due to this laser treatment could be determined. Angular hole burning could easily be detected in these systems.