White LED offers advantageous properties such as high brightness, reliability, lower power consumption and long lifetime. White LEDs are expected to serve in the next generation of lamps. An indoor visible-light communication system utilizing white LED lights has been proposed from our laboratory. In the proposed system, these devices are used not only for illuminating rooms but also for an optical wireless communication system. Generally, plural lights are installed in our room. So, their optical path difference must be considered. In this paper, we discuss about the influence of interference and reflection. Based on numerical analyses, we show that the system is expected to be the indoor communication of the next generation.

Fundamental analysis for visible-light communication system using LED lights

Ultraviolet (UV) disinfection is now an accepted technology for inactivation of a variety of waterborne pathogens in wastewater and drinking water. However, the techniques used in much of the previous research aimed at providing information on UV effectiveness have not yet been standardized. Thus in many peer reviewed published literature, it is not clear how the UV irradiations were carried out, nor how the average \Ifluence\N (or UV dose) given to the microorganisms has been determined. A detailed protocol for the determination of the fluence (UV dose) in a bench scale UV apparatus containing UV lamps emitting either monochromatic or broadband UV light was developed. This protocol includes specifications for the construction of a bench scale UV testing apparatus, methods for determination of the average irradiance in the water, details on UV radiometry, and considerations for microbiological testing. Use of this protocol will aid in standardization of bench scale UV testing and provide increased confidence in data generated during such testing.

Standardization of Methods for Fluence (UV Dose) Determination in Bench-Scale UV Experiments

http://mohan.mse.gatech.edu/publication/1999_Chem%20Rev_v99_p1935.pdf

Nano-Optics in the Biological World: Beetles, Butterflies, Birds, and Moths.

Life on earth is subject to alternating cycles of day and night imposed by the rotation of the earth. Consequently, living things have evolved photodetective systems to synchronize their physiology and behavior with the external light-dark cycle. This form of photodetection is unlike the familiar "image vision," in that the basic information is light or darkness over time, independent of spatial patterns. "Nonimage" vision is probably far more ancient than image vision and is widespread in living species. For mammals, it has long been assumed that the photoreceptors for nonimage vision are also the textbook rods and cones. However, recent years have witnessed the discovery of a small population of retinal ganglion cells in the mammalian eye that express a unique visual pigment called melanopsin. These ganglion cells are intrinsically photosensitive and drive a variety of nonimage visual functions. In addition to being photoreceptors themselves, they also constitute the major conduit for rod and cone signals to the brain for nonimage visual functions such as circadian photoentrainment and the pupillary light reflex. Here we review what is known about these novel mammalian photoreceptors.

/pdf/intrinsically-photosensitive-retinal-ganglion-cells-45lncuzga4.pdf

Intrinsically Photosensitive Retinal Ganglion Cells

White LED offers advantageous properties such as high brightness, reliability, lower power consumption and long lifetime. Indoor optical wireless communication systems employing white LED lighting have been proposed. This system will enable high quality of service by the high radiation power from this lighting equipment. And, this system does not cause or suffer from radio or electromagnetic interference. But, it is difficult for existing offices and households to install the communication cable to the ceiling. In this paper, an easy wiring system for optical communication using the existing power-line is proposed. This system is emitted as visible-light from LED lighting according to the transmitted signal waveform without demodulating the signal from the power-line. This system is expected to be applicable from the existing illuminant easily like exchanging electric bulbs. This integrated system will surely have a big impact as a new signal transmission system and its economical effect will be great. The basic performance of this system is analyzed. The actual system is built and its feasibility is shown through experiments.

Integrated system of white LED visible-light communication and power-line communication

Introduction to Classical and Modern Optics

The following outline is concerned with definitions, symbols, units, and conversion factors as they occur, and are helpful, in radiometry and photometry. The situation here is more complex than in other areas of optics; this is for several reasons. Sometimes, different terms are used for identical quantities. Certain terms such as candlepower are ill-conceived. Others like nox, phot, glim, skot or scot (identical), bril and brill (different), helios, lumerg, pharos, stilb, talbot, and blondel may merely delight the historian. The impending-we hope-general conversion to the mks system, which should more properly now be referred to as SI, presents us with a unique opportunity for simplifying some of the basic definitions and units, although a solution fully satisfying to all may never be found. The term SI stands for Systbme International-International System of Units-adopted by the Eleventh General Conference on Weights and Measures held 11-20 October 1960 in Paris, France, to which the United States has been a party. In this paper, only SI units are used, but their relationship to other units is also shown. Close cooperation of committees of the International Commission on Illumination, the International Organization for Standardization, the International Electrotechnical Commission, and the SUN Commission of the International Union of Pure and Applied Physics has resulted in the development of a set of terms and symbols that is receiving acceptance throughout the entire world. The symbols in the U. S. A. Standard Letter Symbols for Illuminating Engineering (USAS

Radiometry and Photometry: Units and Conversion Factors

Although often colorful and of historical interest, some radiometric and photometric units are redundant and illogical. The essential units are few in number. These, together with their definitions and conversion factors, are presented here.

Radiometry and photometry: units and conversion factors.

Microscopic color schlieren system using a wedge-type interference filter.

A "schliere", in German, is a local inhomogeneity. Schlieren systems, then, are optical systems designed to detect local inhomogeneities. Schlieren occur when hot water mixes with cold water, when shock waves are generated in a gas, when liquid mixtures are separated into components of different refractive index as in ultracentrifugation, and in many other phenomena involving the presence of temperature, pressure, or density gradients. However, there is no reason to restrict the term schlieren to disturbances that deflect light passing through a medium. If light is reflected off an irregular surface, such irregularities may be called 3 schlieren also. Indeed; schlieren systems, be cause they are easy to adjust, have found wide use for the testing of large mirrors.

Jurgen R. Meyer-Arendt

Papers

Introduction to Classical and Modern Optics

Radiometry and Photometry: Units and Conversion Factors

Radiometry and photometry: units and conversion factors.

Microscopic color schlieren system using a wedge-type interference filter.

A Color Schlieren System Without Image Degradation