Light Recycling Research Articles

403 アルミ合金製大型艇の超塑性ブロー成形技術の開発 : 基礎試験による検討(OS3-1 成形加工の新技術)(OS3 加工新技術)

A boat with an aluminum hull has same advantages of light weight structure, high performance and recycling. Superplastic forming has high flexibility in designing a configuration and reduce cost due to less of assembly parts. This paper describes a study on superplastic blow forming for 5083 aluminum alloy. In this study, properties of the material was investigated and 1/10 small size model forming test was conducted for application of FEM. The results showed the process agreed well and could be used to optimize the forming process of an aluminum hull.

Spontaneous emission model of lateral light extraction from heterostructure light-emitting diodes

We investigate the extraction of light from semiconductor light-emitting diodes made of dielectric multilayer stacks with quantum-well sources. The model is a combination of a rigorous vertical model of dipole emission and an in-plane ray-tracing model. The vertical model is shown to conveniently provide the relevant horizontal decay length of the various kinds of in-plane propagating modes. The proposed combination of the two models accounts for the lateral extraction as well as light recycling in the active layers.

51.3: Cholesteric Color Filters: optical Characteristics, Light Recycling, and Brightness Enhancement

AbstractWe demonstrate for the first time a color filter system, based on reflective cholesteric polymers, which has no major absorptive components. We report the principles of operation, process outline, optical properties, color coordinates, extinction curves, evidence for light recycling, brightness enhancement and related issues.

A new backlighting system using a polarizing light pipe

A new backlight with a polarizing light pipe that has great potential for improving the light yield of a liquid crystal display (LCD) is being developed. The aim is to eliminate the three major absorption losses of a TN LCD, which occur in the dichroic polarizer attached to the thin-film-transistor (TFT) glass, the black matrix on the TFT glass, and the color-filter array. The loss in the dichroic polarizer is reduced by the use of a backlight with a polarizing light pipe which produces linearly polarized light output. Both by theory and by experiment we have shown that the polarizing light pipe produces highly polarized light output under optimum conditions, i.e., a 17:1 polarization ratio in the viewing range from -10° to 10°. The brightness gain by polarization is calculated to be 1.44. The losses in the black matrix on the TFT glass and the absorbing color filter are reduced by making these components reflective, so that the light which was previously absorbed is now reflected back into the backlight for recycling. The backlight with a polarizing light pipe is effective in reusing the reflected light. When a reflective color filter is used, the brightness gain of a backlight with a polarizing light pipe over a conventional backlight is 11.3%. The total potential brightness gain by this method of light recycling is theoretically estimated to be 3.16. Therefore, the total gain of an LCD using a polarizing light pipe and reflective components over a conventional LCD is 4.55. This large gain suggests great potential for the polarizing light pipe.

Demonstration of light recycling in a Michelson interferometer with Fabry–Perot cavities

We describe the first experimental demonstration of light recycling of a Michelson interferometer with Fabry-Perot cavities in the arms of the interferometer. Light recycling is a technique for efficiently using the light in long-baseline interferometers, such as those being proposed for the detection of gravitational radiation. An increase in the interferometer circulating power by a factor of 18 is observed, which is in good agreement with the expected gain given the losses in the system. Several phenomena associated with this configuration of coupled optical cavities are discussed.

Recycling for a cleaner signal

Observation of gravitational waves, the ripples in spacetime emitted by violent cosmic events such as the deaths of stars and the births of black holes, could revolutionize our understanding of astrophysics. Several groups are engaged in attempts to build gravitational-wave observatories based on advanced laser interferometers. Efforts at this frontier have spawned new techniques, such as light recycling and the use of squeezed light to maximize the detectors' sensitivity. A new tool, called dual recycling, has been demonstrated which allows more efficient use of laser light and provides an elegant method of tailoring the bandwidths of these detectors.

Recycling in laser-interferometric gravitational-wave detectors.

Laser interferometers may detect gravitational waves by sensing the strain in space produced by their passage. The resultant change in intensity of an interference fringe must be observable against a background noise due to the statistical fluctuations in the number of detected photons. Optimization of the detector sensitivity thus involves devising an optical system which both maximizes the signal and minimizes the noise. This is attempted in the various arrangements known collectively as light recycling. Here, the performance of these systems is quantitatively assessed. Standard or broadband recycling functions essentially by making efficient use of the available light, but it is shown that it may also be made to further enhance the sensitivity within a narrow bandwidth, becoming tuned recycling. This works, as do all the narrow-band variants, by arranging for both the laser light and a gravitational-wave-induced sideband to be resonant in the optical system. The original narrow-band system, resonant recycling, can also be made broadband; the various sensitivity-bandwidth combinations, together with the tuning properties of such a system, are discussed.Furthermore, a new optical arrangement, dual recycling, is proposed. Its optical layout is an extension of standard recycling and its strength lies in its flexibility. It is shown that, relatively simply, it may be made into either a broadband or a narrow-band system, in each case with the same performance as the best of the other schemes. It may be tuned more efficiently and easily over a wide range of frequencies. Uniquely, optimum performance may be obtained with dual recycling without the requirement that the storage time of the optical elements in each arm of the interferometer be comparable with the period of the gravitational wave. This may allow the operation of delay line interferometers down to much lower gravitational-wave frequency and will provide great operational flexibility. Finally, it is shown that dual recycling, together with resonant recycling, is relatively insensitive to imperfections in the geometrical quality of the optical system. When implemented on interferometers with lengths greater than about a kilometer, recycling should allow the attainment of the sensitivity required in order to observe gravitational waves and open up a new window to the Universe.