Kinds Of Optical Devices Research Articles

再帰透過による空中映像における広視野角実現のための直交ミラーアレイの分割配置

We proposed divided-type dihedral corner reflector array (DCRA) in order to display floating image with wide viewing angle. DCRA is a kind of optical device which can display floating image of real object by retrotransmission. The viewing angle of the floating image is, however, narrow, because the angle of incident ray which can be retrotransmission is limited. Therefore, we expand a range of viewing angle by dividing and combining DCRA to use the region in which the ray can be retrotransmission. In this paper, we evaluated the viewing angle of our divided DCRA by analyzing angular distribution of retrotransmissive ratio. As a result, we showed that the divided DCRA can be expanded the viewing angle of floating image to 180 deg.

Sub-50-nm wide slot waveguides with good optical isolation on silicon on insulator

Although slot waveguide structures are widely used in all kinds of optical devices, very few articles focus on the issue of optical isolation of slot waveguides. This article, in an effort to bridge the gap in the available literature, focuses on the aspect of optical isolation of slot waveguides and provides definitive rules for application of different slot waveguides in dense integration of optical links. A slot waveguide with a 48-nm-wide slot was fabricated with electron beam lithography and inductively coupled plasma etching.

Gate-voltage control of angular and spatial shifts for a dielectric slab containing graphene

By theoretically considering a dielectric slab containing graphene, we investigate the effect of the graphene layer on the angular Goos-Hanchen (AGH) shifts and the transverse angular and spatial shifts from the spin-Hall effect of light (SHEL) for the reflection of a light beam. Through manipulating the voltage applied to graphene via an exterior gate, it was found that near the transmission resonance of the slab containing graphene, the giant and tunable AGH shifts and transverse shifts (TS) for both s-polarized and p-polarized waves are present. We also find that near the normal incident angle, the giant and tunable TS from SHEL for both s-polarized and p-polarized waves can occur on the interface containing graphene. It is expected that these phenomena can result in significant interesting and novel applications of graphene in all kinds of optical devices, and more.

Extremely wide band Rayleigh resonant reflector with sharp angular spectra in near infrared wavelength band

In this paper, we propose an extremely broadband Rayleigh resonant reflector with sharp angular spectra operating in near infrared wavelength band, this device consisting of a single germanium resonant grating layer is designed and analyzed by using with the rigorous vector diffraction theory. At the Rayleigh angle, the first diffracted order can be appear from evanescent to a propagating one, thus, a very sharp angular spectrum characteristics can be presented in the device. Based on the guided mode resonant effect, high index material such as silicon and germanium can be designed as wide band reflector, beam splitter and polarizer in near infrared wavelength region. Through connecting Rayleigh phenomena and guided mode resonant effect, we can design a new kind of optical devices with versatile characteristics such as sharp angular spectra and extremely wide reflection band. In this paper, we present a Rayleigh resonant reflector with extremely high reflection (R>99.5%) for TE polarization light over ∼600nm wavelength range and sharp angular spectral distribution. In addition, it is shown from our calculations that the high-index nano-layer located adjacent to the substrate is seen to critically affect the resulting spectra of Rayleigh resonant reflector.

Quantum dots as biophotonics tools.

This chapter provides a short review of quantum dots (QDs) physics, applications, and perspectives. The main advantage of QDs over bulk semiconductors is the fact that the size became a control parameter to tailor the optical properties of new materials. Size changes the confinement energy which alters the optical properties of the material, such as absorption, refractive index, and emission bands. Therefore, by using QDs one can make several kinds of optical devices. One of these devices transforms electrons into photons to apply them as active optical components in illumination and displays. Other devices enable the transformation of photons into electrons to produce QDs solar cells or photodetectors. At the biomedical interface, the application of QDs, which is the most important aspect in this book, is based on fluorescence, which essentially transforms photons into photons of different wavelengths. This chapter introduces important parameters for QDs' biophotonic applications such as photostability, excitation and emission profiles, and quantum efficiency. We also present the perspectives for the use of QDs in fluorescence lifetime imaging (FLIM) and Förster resonance energy transfer (FRET), so useful in modern microscopy, and how to take advantage of the usually unwanted blinking effect to perform super-resolution microscopy.

Optical devices based on multilayer optical waveguide

Optical waveguide is used to guide the transmission of light. This paper reviews multilayer optical waveguide and some devices based on it. The optical waveguide can be divided into single-layer and multilayer optical waveguides in general. Here, multilayer cylindrical waveguide and multilayer planar waveguides were mainly focused. The analyzing method and the structures of waveguides were also demonstrated in briefly. Both these multilayer optical waveguide used in different kinds of optical devices including optical modulator, laser, optical amplifier, optical switch and special fiber were further presented. At last, the principle and structure of these multilayer optical devices were compared.

An image of recurrent time: Notes on cinematic image and the gaze in Béla Tarr’s Sátántangó

Abstract The article deals with Béla Tarr’s longest film Sátántangó and examines relations between image, time and ways of looking, comparing it to Lászlo Krasznahorkai’s 1985 eponymous novel on which the film was based. It reveals connections between episodes and shots in Sátántangó that lead to a conception of time that passes extremely slowly. It is recurrent—leading toward similar, repetitive situations—but at the same represents an inability to change. The image in this film is often conceived as it is mediated and Tarr frequently uses compositions involving ways of looking through some kind of optical device or a window. The only way of accessing reality is to look at it when there is no real opportunity, will or ability to intervene and change it. In this sense the article shows the relationship between the image of the fictional world of Sátántangó, inhabited by passive and demoralized characters, and the world of the film spectator and his or her relation to film image as such.

Novel multifunctional optical device with only axial material parameter spatially variant

Based on the concept of complementary media and theory of coordinate transformation, a novel kind of optical device, exhibiting the multiple performances of a complementary cloak and a transparent device, is proposed. Only the axial material parameter of the proposed device is spatially variant, and the transverse material parameters are constant. The multiple functions of the proposed device are validated by full wave simulations. In addition, the effects of loss and parameter perturbations on the performances of the device are also investigated. These results can be used in field of antenna protection and other electromagnetic field engineering.

Reconfigurable All-Optical Logic Gates for Multi-Input Differential Phase-Shift Keying Signals: Design and Experiments

Differential phase-shift keying (DPSK) signals are promising candidate for the long-haul transmission systems. However, the development of the all-optical signal processing techniques for the DPSK signals is still in its infancy, especially the all-optical logic operations. In this work, a general scheme for reconfigurable logic gates for multi-input DPSK signals with integration possibility is proposed. Benefiting from the optical logic minterms developed by two kinds of optical devices, i.e., optical delay interferometers and semiconductor optical amplifiers (SOAs), target logic functions can be realized by combining specific minterms together. The scheme is reconfigured by changing the phase control of the delay interferometers or the input wavelengths. The latter approach was adopted in the experimental trials. Although the outputs of the scheme are on-off keying (OOK) signals, the data format is compatible with all-optical decision circuits where OOK format is preferred. Two- and three-input experiments are carried out at 20 Gbit/s with nonreturn-to-zero DPSK signals. Various logic operations are demonstrated, including full sets of two- and three-input minterms, AND, NOR, XOR, and XNOR logic operations where the AND and NOR logic are derived simultaneously and the XOR and XNOR logic are convertible. The optical SNR as well as the Q-factor of the two- and three-input results are measured and compared. It shows that the input powers to the SOAs are critical in achieving good extinction ratio and the Q-factor of logic results degrades when several minterms are combined. The recovery time of the SOAs need to be optimized as well. Finally, the scaling issues of the scheme are discussed.

스캐닝 과정에서 발생하는 전자문서의 기하학적 변형감지에 관한 연구

Abstract Scanner which is a kind of optical devices is used to convert paper documents into document image files. The assessment of scanned document image is performed to check if there are any modification on document image files in scanning process. In assessment of scanned documents, user checks the degree of skew, noise, folded state and etc This paper proposed to how to measure geometrical modifications of document image in scanning process. In this study, we check the degree of modification in document image file by image processing and we compare the evaluation value which means the degree of modification in each items with OCR success ratio in a document image file. To analyse the correlation between OCR success ratio and the evaluation value which means the degree of modification in each items, we apply Pearson Correlation Coefficient and calculate weight value for each items to score total evaluation value of image modification degrees on a image file. The document image which has high rating score by proposed method also has high OCR success ratio.

A method of variation of boundaries for waveguide grating couplers

We describe a method for calculating the solution of the electromagnetic field in a non-rectilinear open waveguide by using a series expansion, starting from the field of a rectilinear waveguide. Our approach is based on a method of variation of boundaries. We prove that the obtained series expansion converges and we provide a radiation condition at infinity in such a way that the problem has a unique solution. Our approach can model several kinds of optical devices which are used in optical integrated circuits. Numerical examples will be shown for the case of finite aperiodic waveguide grating couplers.

Control of the properties of directional couplers using proton irradiation

The control of the coupling properties of a directional coupler formed in a planar lightwave circuit by proton irradiation was examined. Irradiation of the cladding between the two cores that constitute the coupling portion causes an increase in the coupling coefficient, whereas subsequent irradiation of the entire coupling portion decreases the coupling coefficient. The change in the coupling coefficient results in changes to the coupling ratios, which depend on the irradiated area and fluence. By adjusting these, the desired coupling property can be obtained. This method can be applied in rectifying fabrication errors in any kind of optical device formed in a planar lightwave circuit.

Alignment control method for liquid crystalline molecules and its application for an all-optical device

A nematic liquid crystalline monomer, containing photocrosslinkable divinyl and azobenzene moieties as functional groups was synthesized. Laser beam irradiation on a liquid crystalline cell of this material is capable of fabricating a very thin cross linked polymer layer on the alignment surface. The crosslinked polymer layer modifies the anchoring force between the alignment surface and liquid crystalline molecules. Meanwhile, the monomeric azobenzene moiety in the bulk interacts with incident light resulting in molecular reorientation through the trans-cis-trans-photoisomerization cycles. Combining the two characteristics mentioned above, a kind of optical device has been proposed. The driving mechanism of this device is the reversible phototriggered switching of the molecular orientation between the homogeneous and the homeotropic state.

Reliability of the OS-280M Optical Submarine Repeater

The development phase of the OS-280M optical submarine cable system is finished, and currently the mass production lines for the system are arranged so as to satisfy the specific performances and the reliability requirements for the TPC-3 system within its system life of 25 years. KDD developed the reliability assurance system of the repeater components, which began three years ago. In this paper, we will introduce the reliability design of the OS-280M system and will report on the reliability test results obtained until the present time. In conclusion, it will be demonstrated that all of repeater components, i.e., optical semiconductor devices, monolithic IC's, several kinds of optical devices, and conventional components could satisfy the reliability requirements for the OS-280M system.

Polarization-independent optical circulator: an experiment

Many kinds of optical devices are being researched in various countries for application in optical fiber communication. Some devices have polarization-dependent characteristics that cause a decrease in the coupling efficiency of the optical fibers. This paper proposes a configuration method using an optical circulator whose characteristics are independent of the polarization condition of the incoming light. Using components such as YIG crystals, polarization prisms, compensating plates, and magnet rings, it was experimentally confirmed that the insertion loss and the isolation were 3.7 dB and 10-20 dB, respectively, at lambda = 1.27 microm and that the polarization dependence was greatly decreased.