Topics in this volume include: beam attenuation; optical properties of turbidity standards; optical absorptions of light and heavy water by laser optoacoustic spectroscopy; and refractive index fluctuations in seawater.

Underwater vehicles and underwater moorings are increasing in tactical importance. As such, it is critical to have a robust and secure communication system connecting underwater vehicles on a long seaborne mission and a ground station. As a matter of fact, the deployment of efficient communication links with underwater vehicles is one of the greatest technological challenges presently confronted by the world's naval forces. To circumvent most of the limitations involved in the use of RF or acoustic channels for perfectly secure communications with underwater vehicles, it is worth considering the feasibility of an optical channel to facilitate a two-way satellite communication link secured via perfectly secure ciphers enabled by a quantum key distribution protocol. This book offers a concise review of underwater communications systems. Our approach is pedagogical, making a strong emphasis on the physics behind the attenuating properties of the oceanic environment and the propagation of electromagnetic signals in the ELF, VLF, and optical bands. We assume the reader is familiar with the basic principles of classical electrodynamics and optics. The system design, components, and noise analysis of an underwater optical communications device are discussed in detail. Furthermore, we offer simulations of the performance of the communication system for different types of ocean waters. Our final conclusion is that it appears to be feasible to design and build underwater communications using optical classical and quantum channels secured with quantum key distribution protocols. Table of Contents: Introduction / Electrodynamics of Attenuating Media / Underwater Communication Channels / Underwater Optical Communications: Technology / Underwater Optical Communications: Noise Analysis / Underwater Optical Communications: System Performance / Underwater Quantum Communications / Conclusions PDF (1764 KB) PDF Plus (1444 KB)

A selection of papers on various aspects of three-dimensional display technology.

SPIE Milestones are collections of seminal papers from the world literature covering important discoveries and developments in optics and photonics.

Elements of Physical Oceanography is a derivative of the Encyclopedia of Ocean Sciences, Second Edition and serves as an important reference on current physical oceanography knowledge and expertise in one convenient and accessible source. Its selection of articles—all written by experts in their field—focuses on ocean physics, air-sea transfers, waves, mixing, ice, and the processes of transfer of properties such as heat, salinity, momentum and dissolved gases, within and into the ocean. Elements of Physical Oceanography serves as an ideal reference for topical research. References related articles in physical oceanography to facilitate further research Richly illustrated with figures and tables that aid in understanding key concepts Includes an introductory overview and then explores each topic in detail, making it useful to experts and graduate-level researchers Topical arrangement makes it the perfect desk reference

This Special Issue is devoted to recent developments in instrumentation and measurement techniques applied to the marine field. ¶The sea is the medium that has allowed people to travel from one continent to another using vessels, even today despite the use of aircraft. It has also been acting as a great reservoir and source of food for all living beings. However, for many generations, it served as a landfill for depositing conventional and nuclear wastes, especially in its deep seabeds, and we are assisting in a race to exploit minerals and resources, different from foods, encompassed in it. Its health is a great challenge for the survival of all humanity since it is one of the most important environmental components targeted by global warming. ¶ As everyone may know, measuring is a step that generates substantial knowledge about a phenomenon or an asset, which is the basis for proposing correct solutions and making proper decisions. However, measurements in the sea environment pose unique difficulties and opportunities, which is made clear from the research results presented in this Special Issue.

The award-winning third edition of 'The Underwater Photographer' dragged the topic kicking and screaming in to the digital age and with the fully updated fourth edition highly respected photographer and tutor Martin Edge takes you deeper in to the world of Underwater Photography. Practical examples take you step-by-step through the basic techniques from photographing shipwrecks, divers, marine life and abstract images to taking photographs at night. Brand new chapters cover not only highly specialist Underwater Photography techniques such as low visibility/greenwater photography, but also the digital workflow needed to handle your images using the latest software such as Lightroom. Packed with breathtaking images and an easy to read style honed from over twenty years of diving photography courses, this book is sure to both educate and inspire underwater photographers of all skill levels.