ABSORPTION DIGITAL REFRACTOMETRY

THIS PROPOSAL DESCRIBES A NEW METHOD FOR DETERMINING THE REFRACTIVE INDEX AND EXTINCTION COEFFICIENT OF OPTICAL MATERIALS. THIS METHOD IS AN OPTO-ELECTRONIC METHOD, IS COMPLETELY AUTOMATED, EXTREMELY FAST AND IS CAPABLE OF OBTAINING ACCURACIES AND RESOLUTIONS COMPARABLE WITH PRISM SPECTROMETERS. THIS MEASUREMENT METHOD IS CALLED ABSORPTIONDIGITAL REFRACTOMETRY. THE MOST ACCURATE METHOD AT PRESENT FOR OBTAINING REFRACTIVE INDICES IS WITH THE DIVIDED CIRCLE PRISM SPECTROMETER. IT IS CAPABLE OF DETERMINING THE REFRACTIVE INDEX TO SIX DECIMAL PLACES WITH AN ACCURACY OF 1X10-6. HOWEVER, THESE INSTRUMENTS ARE EXTREMELY EXPENSIVE, REQUIRE THE FABRICATION OF AN (UNKNOWN) MATERIAL INTO A "PERFECT" EQUILATERAL PRISM, ARE SPECTRALLY RESTRICTED, PRACTICALLY LIMITED TO TRANSPARENT MATERIALS ANDARE NOT READILY ADAPTED TO AUTOMATION. ABSORPTION DIGITAL REFRACTOMETRY OVERCOMES ALL OF THESE LIMITATIONS. THE EQUATIONS FOR DETERMINING THE REFRACTIVE INDEX AND THE EXTINCTION COEFFICIENT ARE DERIVED USING THE STOKES POLARIZATION PARAMETERS AND THE MUELLER MATRIX FORMULATION. IN THE FINAL SECTION THE PROPOSED LABORATORY CONFIGURATION IS DESCRIBED. IF THE CONCEPT OF ABSORPTION DIGITAL REFRACTOMETRY IS VALIDATED IT IS BELIEVED THAT A COMMERCIAL SYSTEM COULD BE BUILT WHICH WOULD FIND NUMEROUS APPLICATIONSIN THE DEVELOPMENT OF OPTICAL MATERIALS.