Finite-field Studies on the Second-order Hyperpolarlizability of MHBA

As a new nonlinear optical organic material, MHBA (3-Methoxy-4-Hydroxy-Benzaldehyde) crystal^1] has been grown into a size of 70 mm×40 mm×20 mm. Its second-harmonic generation (SHG) is about 30 times larger than that of urea, and has a suitable transparency in the range from 370 nm to 1700 nm. MHBA can be used to realize direct frequency doubling of near infrared diode laser to generate violet-blue light at room temperature. We have discussed its SHG by using finite-field method^2~3]. However there is no report on the third-harmonic generation (THG) properties of MHBA. In this study we will theoretically investigate the molecular second-order hyperpolarizabilities of MHBA.