SBIR-STTR Award

Measuring the inherent optical properties of the ocean has historically been a very difficult problem. The most widely used in-situ sensor has been the transmissometer, which measures the transmission of a light beam over a short pathlength in the water.More recently, sensors have become available that measures light absorption and optical backscattering. Absorption and beam attenuation are nonetheless still very difficult measurements to make in situ, and instruments which attempt to make these measurements require great care in their use and are difficult to calibrate. We therefore propose to investigate new approaches and techniques for measuring inherent optical properties of the ocean in situ that are robust and accurate. This study will involve numerical modeling of high propagation through ocean water under various geometries, computer-aided optical and electrical design, and some benchtop measurements with the goal of developing robust and easy to use ocean optical instruments. At the end of the Phase I effort, we will have a complete design for a new generation ocean-optical instrument that can measure relevant spectral inherent optical properties, as well as temperature and pressure, accurately and reliably. The instrument will be self-contained and compact, requiring as little as a fishing line for its deployment.

Benefits:
Knowledge of water optical properties is critical to many areas of ocean science, remote sensing, environmental monitoring, and certain naval applications. Instruments which can measure key optical parameters are already in great demand, and th

Keywords:
lidar optical sensors sensors optical properties remote sensing ocean optics

Characterizing and understanding the optical properties of ocean waters has wide applications ranging from underwater imaging to lidar to ocean-color remote sensing. To properly design optical systems that observe the oceans, and to accurately interpret their data, it is necessary to have knowledge of the absorption and scattering properties of the ocean waters in which they operate. Although absorption can already be measured by a variety of techniques and instruments, measuring light scattering remains the most outstanding measurement problem in ocean optics today. We propose to address this problem by developing a new instrument that can accurately measure the volume scattering function (VSF) of ocean waters. This sensor will be an in-situ profiling instrument that measures the VSF from 0.1 to 170 degrees. The technology we will develop in the Phase II program will be "modular" in the sense that we will be able to build in-situ VSF sensors for measuring specific aspects of light scattering in the ocean, including near-forward and backward scattering, as well as polarization and turbulence effects.