Strangelet search and particle production studies in Pb+Pb collisions at 158 AGeV/c at CERN SPS

We searched for long-lived strange quark matter particles, so-calledstrangelets, and studied particle and antiparticle production in Pb+Pb collisions at 158 GeV/c per nucleon at zero degree production angle. We give upper limits for the production of strangelets covering a mass to charge ratio up to 120 GeV/c ² and lifetimest _lab>1.2 μs and plot invariant differential production cross sections as a function of rapidity for a variety of particles.     

Image holography through convective fog

Light experiences a Doppler frequency shift if it is deflected by scattering on a moving particle. In holography that situation occurs when the light on the way from the object to the hologram passes through moving fog. Due to the Doppler shift the scattered light cannot interfere with the undisturbed reference wave. Hence only the unscattered portion of the object wave contributes to the interference fringes on the hologram. Therefore the reconstructed image is not blurred due to scattering in the fog. We present a simple theory of holographic vision through fog and some verifying experiments.     

The measurement of motion trajectories by speckle photography

We present a method for studying the lateral motion of a body with a rough surface. A speckle photograph of the moving body is recorded in addition to a still photograph of the same body. The total photograph is then optically Fourier transformed and recorded. Yet another optical Fourier transform yields a display of the motion path (‘trajectory’) of the moving body.     

Deciphering vibration holograms

In vibration holography one measures the temporal Fourier coefficients of the complex amplitude emanating from the vibrating object. However, the user wants to know the temporal Fourier coefficients of the mechanical vibration itself. The mechanical vibrations are proportional to the phase of the complex light amplitude. Hence, the temporal Fourier coefficients of the mechanical vibrations depend in a complicated manner on the temporal Fourier coefficients of the complex amplitude itself. So far, either narrow approximations or complicated Bessel algorithms were used for deducing the mechanical Fourier coefficients from the optical Fourier coefficients. In other words, deciphering the mechanical data from the optical measurements was not easy.We propose a simple and rigorous algorithm for this deciphering project. In addition we outline a holographic experiment that allows one to reconstruct a space- and time-dependent complex amplitude and also its temporal derivative. This experiment is capable of displaying the mechanical velocity distribution as image brightness. Also the spatial distribution of mechanical acceleration can be displayed.     

The ambiguity function as a polar display of the OTF

It is shown that the Ambiguity function of the generalized pupil function of an optical system, is a polar display of the optical transfer function with the focus error as variable. This geometrical interpretation allows one to obtain the OTF for any given amount of defocus.     

Ionenadsorption an der Grenzfläche Oxid/Elektrolyt

Summary Adsorption of ions at the oxide/electrolyte interface is explained by a model which compares adsorption and complex formation of the corresponding ions in solution.     

Two-way code translation by computer-generated holographic filters

In two-way code translation, we want to design a single holographic filter that can work in two directions: It converts one specific image into a second associated image, and it can also convert the second image into the first image. Such a filter could be used perhaps as an associative memory. To generate the filter phase properly for the two filtering processes, we can use two complex conjugate filter functions, as they are incorporated automatically in a holographic filter. The filter amplitude cannot in general be made exactly correct for both filtering processes. We investigated different error criteria for the optimization of the filter amplitude, with and without noise in the input. Computer simulations are shown.     

Image subtraction by polarization-shifted periodic carrier

A coherent image subtractor is described that makes use of a periodic carrier that is effectively shifted by one-half period by simple sheet polarizing material. As the system has two input stations, the two transparencies to be subtracted are simultaneously visible to facilitate alignment.