"BIOPOLYMER - BASED NONLINEAR OPTICAL MATERIALS"

RECENT DEVELOPMENT OF MATERIALS WITH LARGE SECOND AND THIRD ORDER NONLINEAR EFFECTS HAS GENERATED INTEREST IN APPLICATIONS TO FUTURE TELECOMMUNICATIONS AND ELECTRONIC SYSTEMS. THE IDEAL NONLINEAR OPTICAL MATERIAL (NLOM) FOR MOST APPLICATIONS WOULD HAVE A VERY LARGE NONLINEAR RESPONSE, EXTREMELY LOW SWITCHING THRESHOLDS AND RAPID SWITCHING TIMES. POPULAR APPROACHES FOR THE GENERATION OF POLYMERS EXHIBITING SECOND HARMONIC GENERATION (SHG) INCLUDE POLING LINEAR POLYMERS OR NETWORKS CONTAINING DISSOLVED, NLO-ACTIVE CHROMOPHORES, OR POLYMERS TO WHICH SUITABLE CHROMOPHORES HAVE BEEN COVALENTLY ATTACHED. HOWEVER, CHROMOPHORE ALIGNMENT DURING POLING IN THESE MATERIALS IS NEVER PERFECT. RATHER, A DISTRIBUTION OF ALIGNMENT DIRECTIONS EXISTS, AND OF COURSE THE NLO RESPONSE IS COMPROMISED. WE BELIEVE THAT BIOPOLYMERS OFFER THE BEST OPPORTUNITY TO ACHIEVE VIRTUALLY COMPLETE ALIGNMENT OF CHROMOPHORES. THE PHASE I WORK IS DIRECTED TO DEVELOPMENT OF NONLINEAR OPTICALLY (NLO) ACTIVE MATERIALS WITH ENHANCED SECOND HARMONIC GENERATION (SHG) BASED ON NONCENTROSYMMETRIC BIOPOLYMERS. POLYPEPTIDES (MOLECULES WITH CHIRAL SPATIAL CONFIGURATIONS) WILL BE DERIVATIZED TO BEAR MOIETIES WITH FINITE MOLECULAR POLARIZABILITY. INVESTIGATIONS INCLUDE (1) POLYPEPTIDES DIRECTLY DERIVATIZED WITH SIMPLE POLARIZABLE SIDE GROUPS, AND (2) KNOWN SHG MATERIALS "DERIVATIZED" WITH POLYPEPTIDES. SHG EFFICIENCY NORMALIZED TO UREA OR KDP WILL BE DETERMINED AT 532 NM USING THE 1064 NM FUNDAMENTAL OUTPUT OF A Q-SWITCHED ND:YAG LASER.