RARE EARTH ENDOHEDRAL FULLERENES AS NEW NONLINEAR OPTICAL MATERIALS

COMPUTERS USING LIGHT BEAMS INSTEAD OF WIRES ARE THE FASTEST KNOWN TYPE OF COMPUTER. MANY OF THE MAIN COMPONENTS OF OPTICAL COMPUTES SUCH AS THE OPTICAL SWITCHES THAT ARE ITS FUNDAMENTAL BUILDING BLOCKS ARE FABRICATED FROM THIRD ORDER NONLINEAR OPTICAL (NLO) MATERIALS. UNFORTUNATELY, THE BEST CURRENTLY AVAILABLE THIRD ORDER MATERIALS HAVE NLO EFFECTS THAT ARE TWO TO FOUR ORDERS OF MAGNITUDE SMALLER THAN ARE NEEDED FOR COMMERCIAL DEVICES DRIVEN BY MODERATE POWER DIODE LASERS. ENDOHEDRAL FULLERENES (CLOSED CAGE CARBON MOLECULES WITH A RARE EARTH ATOM OR ATOMS TRAPPED INSIDE) ARE BELIVED TO POSSESS LARGE OPTIAL NONLINEARITITES. SIGNIFICANTLY, THESE PREDICTED NONLINEAR EFFECTS ARE OPTIMALLY LOCATED FOR USE WITH INFRARED (IR) LASER DIODES. ADDITIONALLY, ELECTRONIC INTERACTIONS BETWEEN THE FULLERENE AND METAL ATOM MAY PROVIDE A NATURAL WAY TOOPTICAL CONTROL OF THE MATERIALS PROPERTIES AND ALLOW FOR OPTICAL SWITCHING OF THE NONLINEARITY. IN SPITE OF THE FACT THAT ENDOHEDRAL FULLERENES WERE FIRST PRODUCED ALMOST THREE YEARS AGO, INSUFFICIENT MATERIAL EXISTS TO DETERMINE IF THEY ACTUALLY HAVE THE NLO PROPERTIES PREDICTED BYTHE THEORISTS. THIS IS PRIMARILY A RESULT OF THE DIFFICULTY IN PURIFYING THE MATERIALS. THEREFORE, IN PHASE I A NEW TYPE OF LARGE SCALE PRECONCENTRATION STEP WILL BE USED ALONG WITH HIGH PERFORMANCE LIQUID CHROMATOGRAPHY TO PURIFY SUFFICIENT QUANTITIES OF ENDOHEDRAL FULLERENES FOR NLO CHARACTERIZATION. THE OPTICAL PROPERTIES OF THE MATERIALS WILL BE MEASURED USING FOUR WAVE MIXING SPECTROSCOPY AND OTHER TYPES OF NONLINEAR SPECTROSCOPY.