Computer generated polarization holograms: phase recording by polarization effect in photodichroic materials

A new algorism of computer holography utilizing the anisotropic interaction of light with photodichroic materials is proposed. The most unique feature of this technique lies in the realization of phase information recording without the use of detour phase or optical path difference effect. Basic principles of information recording and reconstruction scheme using M centers in alkali halide crystals such as sodium fluoride are described in detail, and several technical merits and problems associated with the proposed algorism are discussed. This new method will provide a real-time holographic system where accurate recordability and high storage capacity are attainable due to its possibility of recording a calculated complex amplitude of wavefront only by means of controlling the polarization direction of illuminating beam.

Combined use of surface and perfusion hypothermia in intracardiac surgery in infants under one year of age

Deep hypothermia has recently gained popularity as an adjunct to intracardiac surgery for neonates and infants. A number of Japanese investigators played a role in the development and clinical application of both simple surface-induced hypothermia and the combined use of surface and perfusion cooling. The developmental history of both methods is described in detail. At the Heart Institute of Japan, 71 infants under one year of age underwent intracardiac surgery over the past six years. There has been a notable decrease in operative mortality since the employment of circulatory arrest under deep hypothermia and limited pump-perfusion. This trend is marked in infants with ventricular septal defect and pulmonary hypertension, and in those with total anomalous pulmonary venous connection. The Landé-Edwards membrane oxygenator proved helpful in prevention of postoperative pulmonary complications.

Automatic character reading using a holographic data processing technique

One of the useful applications of holography is information conversion. This paper reports on a newly developed automatic character reading system using code-transform holograms for analog-digital (A-D) conversion. Unknown characters are recognized by converting spatial analog character information to spatial digital information. System parameters are sampled out, and important factors such as (1) discrimination, (2) storage capacity, and (3) reading speed, which determine the performance of this system, are discussed.