The Path from a Digital Versatile Disc (DVD) using a Red Laser to a DVD using a Blue Laser

Abstract

The physical and chemical properties of plutonium are related to its environmental transfer and uptake by man. Once incorporated, plutonium is avidly retained in the lungs, liver and skeleton, the relevant amounts being determined by its solubility in body fluids. A knowledge of the toxicity of plutonium is largely dependent upon animal studies where exposure to relatively large amounts, compared with those associated with known human exposure, can cause tumours in those tissues where it is retained. With one exception, epidemiological studies have not been able to demonstrate adverse health effects in humans.Precautions taken in the processing of plutonium have ensured that average intakes by workers have been consistently low. When it has been released to the environment, it has been of little ecological importance and has caused only small doses to man with no observable adverse effects.The long half-life of plutonium causes anxiety about its storage and disposal, but plutonium is not unique. It is often forgotten that very much larger amounts of permanently toxic elements such as arsenic, cadmium and lead are stored and disposed of with much less concern. Plutonium is a valuable resource and for that reason should not be treated as a waste for disposal into the environment.

Current Developments in Optical Data Storage with Organic Dyes

“…[8] The new formats BluRay and HD-DVD (high-definition-DVD, previously known as advanced optical disc, AOD) currently under discussion have storage capacities of 25 GB and 15 GB, respectively. [9][10][11] Both formats use blue laser diodes (l = 405 nm) to play and record the data. Otherwise these formats have little in common ( Figure 5).…”

Optical Second-Harmonic Generation in Benzophenone

“…Introduction Versatile and efficient sources of blue light are of fundamental importance for various applications including optical data storage [1,2], ophthalmologic or other medical techniques [3], and laser displays [4 to 6]. In spite of the rapid development of blue laser diodes [7,8] and concurrent physical principles like optical upconversion [9], the optical second-harmonic generation [10] (SHG) still is one of the most important methods to achieve intense coherent blue light with a good optical beam quality [11].…”

Growth and characterization of new nonlinear optical l-threonium acetate single crystals

“…Versatile and efficient sources of blue light are important requirements for various applications including optical data storage, ophthalmologic or other medical techniques, and laser displays [1]. In spite of the rapid development of blue laser diodes and concurrent physical principles like optical upconversion, optical second-harmonic generation (SHG) is still one of the important methods to achieve intense coherent blue and green light with good optical beam quality [2].…”