A REFERENCE STANDARD RETICLE FOR OCEAN OPTICAL INSTRUMENTS

A TECHNIQUE IS BEING DEVELOPED FOR THE IN-SITU CALIBRATION OF OCEAN OPTICS INSTRUMENTS. THE TECHNIQUE IS BASED ON USING A RETICLE TO SIMULATE THE SCATTERING AND ABSORPTION PROPERTIES OF OCEAN WATER. THESE TWO INHERENT PROPERTIES ARE THE KEY PARAMETERS DESCRIBING THE PROPAGATION OF LIGHT UNDERWATER, AND A NEW GENERATION INSTRUMENT TO MEASURE THEM IS CURRENTLY BEING DEVELOPED IN PHASE I OF THIS PROJECT. THE CALIBRATION RETICLE CONSISTS ESSENTIALLY OF THIN FILMS OF OPAQUE METAL, DEPOSITED ON A GLASS SUBSTRATE, THAT ACT AS SMALL MIRRORS, THUS PRODUCING BOTH FORWARD AND BACKWARD DIFFRACTION PATTERNS. SPECTRAL CALIBRATION WILL BE ACHIEVEDBY USING AN IONICALLY COLORED GLASS WITH DISTINCT NARROWBANDTRANSMISSION MINIMA IN THE VISIBLE RANGE 094 TO 0.7 MICRONS. THIS PROJECT'S PHASE I TASKS ARE TO DESIGN THE RETICLE AND TEST IT USING FRAUNHOFER DIFFRACTION MODELS. THE PHASE II AIM IS TO FABRICATE RETICLES USING PHOTOMASK TECHNIQUES AND TO INCORPORATE THEM INTO EXISTING OR DEVELOPMENTAL INSTRUMENTS.