Third-Order Nonlinear Optical Interactions in Tetrabenzporphyrins

Third-order nonlinear optical susceptibility χ(3) was measured for a variety of tetrabenzporphyrin compounds in solution in tetrahydrofuran at 532 nm using the technique of degenerate four-wave mixing. High values in the range 10−9 to 10−8 esu are observed. The dominant contribution comes from the imaginary part as a result of excited state absorption. Measurements were also made on thin films, deposited by the Langmuir-Blodgett technique, for one of the compounds. Mirrorless all-optical bistability induced by reverse saturable absorption was observed. These materials are good candidates for some applications in photonics technology.