Accession Number : AD1026301


Title :   Optical Attenuation Coefficient Meter


Descriptive Note : Technical Report


Corporate Author : Naval Undersea Warfare Center Newport United States


Personal Author(s) : Estes,Lee E


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/1026301.pdf


Report Date : 22 Jun 2016


Pagination or Media Count : 19


Abstract : An attenuation meter is provided for use in a water environment. In operation, a transmitter of the meter transmits a laser pulse focused to a size at a predetermined range. A receiver of the meter images a focused spot to minimize unwanted light back scattering and avoid diffractive spreading within the back scattering region. Filtering the angular spectrum can further reject scattered light. The filtered light is received, measured and processed by a oscilloscope as pulse averages. The meter also includes a photodetector to measure a diffuse attenuation coefficient. The output voltage of the photodetector is measured and processed by the oscilloscope that produces an average voltage over a preset number of pulses. A controller best fits voltage to time dependence to produce the diffuse attenuation coefficient. Only the shape of the receiver time dependence is required to provide the diffuse attenuation coefficient measurement.


Descriptors :   attenuation , transmitters , laser pulses , scattering , photodetectors , inventions , coefficients


Subject Categories : Optical Detection and Detectors


Distribution Statement : APPROVED FOR PUBLIC RELEASE