Patent ID: 9684077
Date: 2017-06-20
CPC Classifications: G01B,G01S,H01S,H04B

Claim:
1. An apparatus comprising: an infrared laser outputting a laser signal having a first wavelength between 1800 nm and 2000 nm as an intermediate optical signal output beam; a frequency quadrupler operably coupled to receive the intermediate optical signal output beam and to output a frequency-quadrupled optical signal; a beam polarizer configured to orient a polarization direction of the frequency-quadrupled optical signal in a direction that enhances transmission through an air-water interface; a beam transmitter operably coupled to transmit the polarized frequency-quadrupled optical signal through water; a light detector and processor configured to detect and process reflections from the transmitted frequency-quadrupled optical signal to generate image data, wherein the light detector includes a narrowband light filter configured to increase a signal-to-noise ratio of the detected reflections.