OPTICALLY ADDRESSED MODULATOR MATERIALS

FLUORIDE MATERIALS HAVE BEEN IDENTIFIED AS PROMISING CANDIDATES FOR HIGH-POWER OPTICAL SIGNAL PROCESSING APPLICATIONS, ESPECIALLY FOR THOSE IN WHICH SECOND HARMONIC GENERATION (SHG) FIGURES IN THE ELECTRONIC TRANSITIONS LEADING TO NONLINEARITY IN THE OPTICAL SUSCEPTIBILITY. THEY HAVE BEEN GIVEN THIS RECOGNITION DUE TO THEIR HIGH TRANSPARENCY, LOW DISPERSION, AND LOW ANGULAR SENSITIVITY. PREVIOUSLY INVESTIGATED FLUORIDE MATERIALS ARE RESTRICTED TO HIGHPOWER APPLICATIONS BECAUSE NONLINEAR RESPONSE COEFFICIENTS ARE ORDINARILY LOW. IT HAS BEEN SUGGESTED THAT LARGE NONLINEAR RESPONSES CAN BE ACHIEVED USING FLUORIDE STRUCTURES CONTAINING TRANSITION METAL IONS. THIS CLAIM IS MADE AS A CONSEQUENCE OF IMPORTANT CONTRIBUTIONS TO THE DIELECTRIC RESPONSE FROM LIGAND TO METAL CHARGE TRANSFER TRANSITIONS ASSOCIATED WITH COORDINATION CLUSTERS AROUND THE TRANSITION METALS. IT HAS FURTHER BEEN SUGGESTED THAT DETAILS IN GEOMETRIC STRUCTURE PLAY A SECONDARY ROLE TO COMPOSITIONAL FACTORS IN DETERMINING X(3). ON THE BASIS OF THESE FINDINGS, SPEC-TRAN PROPOSES DEVELOPING OPTICALLY ADDRESSED MODULATOR MATERIALS BY DOPING HEAVY METAL FLUORIDE GLASSES WITH OPTICALLY ACTIVE TRANSITION METAL IONS.