THIRD-ORDER NONLINEAR OPTICAL MATERIALS

NEW ORGANIC NONLINEAR MATERIALS HAVE BEEN DESIGNED TO HAVE LARGE THIRD-ORDER NONLINEARITIES, HIGH RESPONSE SPEEDS, HIGH DAMAGE THRESHOLDS, AND ABSORPTION EDGES BELOW BLUE. THE TYPICAL NONLINEARITY OF DESIGNED MATERIALS IS HUNDREDS OF TIMES HIGHER THAN UREA, THE ABSORPTION EDGE IS AS LOW AS 388 NM, AND THE MELTING POINT (MANAGE THRESHOLD) IS 180C. FOUR OF SUCH DESIGNED MATERIALS HAVE BEEN SYNTHESIZED. THEIR ABSORPTION SPECTRA, NONLINEARITIES (IN POWDER), AND MELTING POINTS HAVE BEEN MEASURED. THE DESIGN PRINCIPLES LIE IN THE FACT THAT EXTENDING THE CONJUGATED PI-BOND LENGTH MAY ENHANCE THE NON-LINEARITY BUT MAY PREVENT THE RAPID RESPONSE AND WIDE TRANSPARENT BAND. TO BENEFIT BOTH THE NONLINEARITY AND THE RESPONSE SPEED, THE DESIGN EMPHASIS HAS BEEN PUT ON DETERMINING THE PROPER COMBINATION OF A CONJUGATED PI-BOND LENGTH AND AN ACCEPTOR-DONOR PAIR.