Large second-harmonic generation coefficients of bis(benzylidine) cycloalkanones estimated by the second-harmonic wave generated with the evanescent wave technique

The second-harmonic generation (SHG) coefficients (d) in a series of novel organic materials, i.e. bis(benzylidene)cycloalkanones derivatives, were estimated by means of the second-harmonic wave generated with the evanescent wave (SHEW) technique. As a result, it is found that several compounds exhibit a large d coefficient, in pentanone (MBCP). An X-ray crystallographic study reveals that the symmetry of MBCP is orthorhombic mm2. Comparison between d coefficients estimated by the SHEW and the Kurtz technique is also made.