The irradiance pattern was measured for the propagation of a collimated beam of light underwater. A neodymium-doubled green laser was transmitted horizontally at a six foot depth in Lake Winnipesaukee, N.H. The irradiance was measured at distances from 0 to 100 feet and for off-axis angles from 0 to 58 degrees. The water had an attenuation length of 4.54 ft/ln and an absorption coefficient of 0.0446 ln/ft. The ratio of attenuation coefficient to absorption coefficient was 4.94. The fractional power contained within a cone of various angles was computed. At 20 attenuation lengths only 10% of the total power is contained within a cone of 4 degrees whereas at 4 attenuation lengths this same cone contains 50% of the power. (Author).

It is expected that advances in optics will revolutionise the 21st century as they began doing in the last quarter of the 20th. Such fields as communications, materials science, computing and medicine are leaping forward based on developments in optics. This series presents research on optics and lasers from researchers spanning the globe.

Underwater Research is primarily a review of problems in underwater viewing and hearing and acoustics. The chapters in this book are papers collated from the symposia of the Underwater Association. This book explores the need for the further study of the physiological and psychological reactions of divers. The book also concludes that diving is still the best way in studying the benthic ecology and sunken wrecks and cities. The text is divided into 25 detailed chapters. Most of the topics in the text address the common problems encountered by divers such as in hearing and viewing. Specifically, problems in diver communication, depth estimation, color distinction are some of the topics covered. Other chapters deal with the psychological reactions such as anxiety, narcosis, and visual attention. Also, some chapters tackle solutions and experiments for the improvement of diving techniques and equipment. This reference is helpful to divers, students, and scientists involved in marine and environmental science.

Marine Optics

Since the publication of Jerlov's classic volume on optical oceanography in 1968, the ability to predict or model the submarine light field, given measurements of the inherent optical properties of the ocean, has improved to the point that model fields are very close to measured fields. In the last three decades, remote sensing capabilities have fostered powerful models that can be inverted to estimate the inherent optical properties closely related to substances important for understanding global biological productivity, environmental quality, and most nearshore geophysical processes. This volume presents an eclectic blend of information on the theories, experiments, and instrumentation that now characterize the ways in which optical oceanography is studied. Through the course of this interdisciplinary work, the reader is led from the physical concepts of radiative transfer to the experimental techniques used in the lab and at sea, to process-oriented discussions of the biochemical mechanisms responsible for oceanic optical variability. The text will be of interest to researchers and students in physical and biological oceanography, biology, geophysics, limnology, atmospheric optics, and remote sensing of ocean and global climate change.

This textbook covers all related communication technologies of underwater wireless communication, such as acoustic communication, optical communication, and magneto-inductive communication. After describing each technology, the authors relay their pros and cons, as it is essential to learn the underlying mechanism, advancements, and limitations of these techniques. Therefore, this book provides basics fundamentals of the three technologies, their advantages and disadvantages, and their applications. The authors also introduce research trends, pointing readers in the direction of research in the field of underwater wireless communication. The book is an essential textbook for undergraduate and graduate students in the field of underwater communications. The book is also useful as a reference to undergraduate engineering students, science students, and practicing engineers. The book includes end-of-chapter questions and numerical problems.