Simulation of Differential Phase Detection Method Combined with Astigmatic Method using a Half Mirror in an Optical Pick-up

In an error detection optical system for optical pick-ups using a parallel plane type half mirror, influence on the differential phase detection (DPD) signal by a coma aberration was simulated. The coma aberration deforms the spot profile on the photodetector and influences the DPD signal level characteristics and the offset characteristics with respect to the objective lens shift. In the 4-segment-type DPD, the coma aberration caused by a half mirror 2.75 mm thick hardly affects the DPD signal if the photodetector is not misaligned. On the other hand, the 2-segment-type DPD has a small offset variation with respect to the objective lens shift and a large variation of the DPD signal level against the misalignment of the photodetector in comparison with the 4-segment-type DPD when there is no coma aberration. In the presence of a coma aberration, however, these variations of the 2-segment-type DPD are suppressed by choosing a pair of elements without the coma apex part of the spot.     

SPECTROSCOPIC STUDIES ON THE STRUCTURES OF RETINOCHROME and METARETINOCHROME*

Abstract– Spectroscopic measurements of retinochrome and the related photoproduct, metaretino-chrome, were carried out to determine the conformation of the retinal and the protein. Absorption spectra with fourth derivatives indicate that the tryptophan residues are located in a hydrophobic core and that the environment around these residues does not change after light irradiation. Circular dichroism measurements indicate that retinochrome has a high helical content which is not altered by the conversion of retinochrome to metaretinochrome. Fourier transform infrared difference spectra demonstrate that retinochrome has the all-trans retinal and metaretinochrome has the 11-CM retinal. Retinochrome has an absorption due to amino acid residue(s) which changes in metaretinochrome. This work demonstrates that conformational changes are not induced during the conversion but the electrical charge(s) of the protein are changed by irradiation.     

New Disk Structure for Million Cycle Overwritable Phase Change Optical Disk

The overwrite cycle characteristics and environmental stability of a phase change optical disk with a new disk structure were demonstrated. The C/N ratio was around 55dB, the erase ratio was around 25dB and the phase jitter was under 50% throughout the one million cycle overwrite test. The accelerated aging test conditions were 90°C, 80%RH, for 600 hours and 70°C, 80%RH for 5,200 hours. The archival and shelf one million overwrite cycle characteristics of phase jitter were stable throughout the aging test. The life expectancy of the disk is anticipated to be more than 60 years in a 32°C, 80%RH environment.Presented at the International Commission for Optics Topical Meeting, Kyoto, 1994.     

Simulated Output Images of Near-Field Optics by Volume Integral Equation: Object Placed on the Dielectric Substrate

We investigated near-field optical (NFO) imaging characteristics of a small object placed on a dielectric slab by a computer-code using a three-dimensional volume integral equation with an effective iteration technique called the generalized minimal residual method. A simplified three-dimensional NFO microscope that consists of a small dielectric object placed on the dielectric substrate and a small dielectric sphere as a scanning probe-tip was considered. Calculating two-dimensional output images obtained from scattered far fields, we studied the effect of the substrate on NFO output images, the comparison of NFO output images with electrostatic field around the small object, the dependence of output image characteristics on the wavelength and the difference of imaging characteristics between incident plane waves and incident evanescent waves.     

Smooth perturbations the self–adjoint operators defined by the ℋ︁–2–construction

The existence of the wave operators for the self–adjoint operator constructed by ??_–2–construction is discussed in the abstract theory by using Kato's smooth perturbation method. Moreover, the s–matrix is calculated explicitly.     

SOA Direct Modulation in Wavelength-Selectable Laser Array Light Sources

We demonstrated, for the first time, 2.5-Gb/s SOA direct modulation in the wavelength-selectable DFB laser array. The SOA direct modulation was achieved in the wide tuning range of 22.7nm by selecting arrayed laser and tuning the temperature. 40-km transmission was also confirmed..     

Broadband IP Stream Transmission Experiments over Global and Long Distance Networks

Super High Definition (SHD) movies were successfully transmitted as streaming contents at about 300 Mbps for the first time over a long distance IP network (more than 3,000 km), in conjunction with the experimental verification of traffic control and scalable multicast technologies.     

Physical properties and structure of silk. VI. Conformational changes in silk fibroin induced by immersion in water at 2 to 130°c

Silk fibroin films in the random-coil and β-form conformations were immersed in water at temperatures from 2 to 130°C, and conformational changes were followed by x-ray diffraction, infrared spectroscopy and differential scanning calorimetry. On treatment with water below 60°C, the random-coil conformation is converted to the α form and above 70°C to mixtures of the α and β conformations. The β-form content increases as the immersion temperature is raised. The β form is not affected by immersion in water in the temperature range studied.     

Perchlorate-selective electrodes with urushi as the membrane matrix

Perchlorate-selective electrodes prepared from a new matrix, Urushi, and tri-n-octylmethylammonium perchlorate or the Corning perchlorate liquid ion-exchanger are described. The electrodes have linear response ranges and selectivity similar to those of commercial perchlorate-selective electrodes. The membranes are hard, lustrous and smooth; their useful lifetimes exceed 1000 h.