Biosynthesis of carotenoids in Brevibacterium sp. KY-4313

The biosynthesis of 4-keto and 4,4'-diketo carotenoids in Brevibacterium sp. KY-4313 was studied. Echinenone and canthaxanthin were isolated from the cultures grown on a medium containing several n-alkanes. When glutathione was added to the bacterial cultures, the formation of canthaxanthin was inhibited while beta-carotene and its hydroxy derivatives accumulated. It is suggested that these 4-hydroxy compounds, isocryptoxanthin, isozeaxanthin, and 4-hydroxy-4'-keto-beta-carotene, are intermediates in the biosynthesis of canthaxanthin. In the presence of 2-(4-chlorophenylthio)-triethylamine hydrochloride or nicotine, lycopene and neurosporene accumulated. The beta-carotene level decreased slightly but beta-zeacarotene remained unchanged. beta-carotene and its derivatives were resynthesized upon removal of the inhibitors. It was concluded that cyclization can take place at either the neurosporene or lycopene level in Brevibacterium sp. KY-4313.

Holographic recording on thermoplastic films

Experimental results related to holographic recording on thermoplastic films will be given. Covered are the following areas: the various recording processes, the photosensitivity measurements, the induced frost, the deformation growth process, the bandwidth problem, and the corona damage. These, aspects are of relevance to the thermoplastic's being used as a storage medium in a read-write holographic memory. A specific recording process will be reported that possesses the combined advantages of consistency, high diffraction efficiency, and large bandwidth recording.

Advanced optical storage techniques for computers

The growing demand for data storage in computing systems has stimulated the investigation of optical memory techniques because they offer a potential improvement in packing density of about two orders of magnitude over the apparent limits of conventional magnetic storage techniques. Physical properties and optical memory characteristics of magnetooptic thin-films of manganese bismuth have been investigated with regard to both bit-oriented and holographic memories. All the required technology for design of a bit-oriented memory appears to be available, but several key components required for a holographic memory still remain to be developed.

Geometrical interpretation of gaussian beam optics

The relationship between conventional optics and Gaussian beam optics is discussed. Geometrical concepts such as image and object planes, pupil plane, F-number, resolution, and depth of field are discussed for Gaussian beams and are given a precise meaning in terms of the Gaussian beam parameters. The approach is useful in the design of laser scanning systems and holographic optical memory systems.

MnBi Films as Potential Storage Media in Holographic Optical Memories

Because of its alterability and stability, an MnBi thin film is a potential candidate for the storage medium in a read-write-erase in situ holographic optical memory. The conditions and the physical mechanism of holographic storage will be discussed, together with experimental results. A simple holographic memory system will be proposed which uses the same write-in reference beam for readout beam.